CN112736298A

CN112736298A - Hybrid electrochemical cell design with voltage modification

Info

Publication number: CN112736298A
Application number: CN201910978022.8A
Authority: CN
Inventors: 苏启立; 刘海晶; 吴美远; 孔德文; 侯孟炎
Original assignee: GM Global Technology Operations LLC
Current assignee: GM Global Technology Operations LLC
Priority date: 2019-10-15
Filing date: 2019-10-15
Publication date: 2021-04-30
Also published as: DE102020125081A1; US11651906B2; US20210110980A1

Abstract

The present invention relates to a hybrid electrochemical cell design with voltage modification. A hybrid lithium-ion electrochemical cell comprising: a first electrode having a first polarity and a first electroactive material having a first maximum operating voltage that reversibly cycles lithium ions, and a second electrode having a first polarity and a second electroactive material having a second maximum operating voltage. The difference between the second and first maximum operating voltages defines a predetermined voltage difference. Also included are at least one third electrode having a second polarity opposite the first polarity, comprising a third electroactive material that reversibly cycles lithium ions, a separator, and an electrolyte. A voltage changing component (e.g., a diode) is in electrical communication with the first and second electrodes. In a first operating state corresponding to charging, the at least one voltage change component is configured to induce a voltage drop corresponding to the predetermined voltage difference, providing a high power density and high energy density hybrid lithium-ion electrochemical cell.

Description

Hybrid electrochemical cell design with voltage modification

Technical Field

Introduction to the design reside in

This section is related to background information of the disclosure and is not necessarily prior art.

The present disclosure relates to hybrid lithium-ion electrochemical cells having high energy capacity and high power capacity. A hybrid lithium-ion electrochemical cell includes a first electrode having a first polarity and a first electroactive material that reversibly cycles lithium ions and a second electrode having the first polarity and a second electroactive material different from the first electroactive material. In some cases where the electrodes have different electroactive materials, they may be limited in operation by a predetermined voltage difference. A voltage changing component (e.g., a diode) is in electrical communication with the first and second electrodes and provides a voltage drop corresponding to a predetermined voltage difference between the first electrode and the second electrode.

Background

High energy density electrochemical cells, such as lithium ion batteries, can be used in a variety of consumer products and vehicles, such as hybrid or electric vehicles. A typical lithium ion battery includes at least one positive electrode or cathode, at least one negative electrode or anode, an electrolyte material, and a separator. Stacks of lithium ion battery cells can be electrically connected in an electrochemical device to increase overall output. Lithium ion batteries operate by reversibly passing lithium ions between a negative electrode and a positive electrode. The separator and the electrolyte are disposed between the negative electrode and the positive electrode. The electrolyte is suitable for conducting lithium ions and may be in solid or liquid form. Lithium ions move from the cathode (positive electrode) to the anode (negative electrode) during battery charging, and in the opposite direction as the battery discharges. Each negative and positive electrode in the stack is connected to a current collector (typically a metal, such as copper for the anode and aluminum for the cathode). During use of the battery, the current collectors associated with the two electrodes are connected by an external circuit that allows the current generated by the electrons to pass between the electrodes to compensate for the transport of lithium ions.

The potential difference or voltage of the battery cell is determined by the difference in chemical potential (e.g., fermi level) between the electrodes. Under normal operating conditions, the potential difference between the electrodes reaches a maximum achievable value when the battery cell is fully charged and a minimum achievable value when the battery cell is fully discharged. When the electrodes are connected via an external circuit to a load, such as an electric motor, which performs the required function, the battery cell will discharge and will obtain a minimum achievable value. Each of the negative and positive electrodes in the battery cell is connected to a current collector (typically a metal, such as copper for the anode and aluminum for the cathode). The current collectors associated with the two electrodes are connected by an external circuit that allows the current generated by the electrons to pass between the electrodes to compensate for the transport of lithium ions across the battery cell. For example, during discharge of the battery, the internal Li from the negative electrode to the positive electrode⁺The ionic current may be compensated by an electronic current flowing through an external circuit from the negative electrode to the positive electrode of the battery cell.

Many different materials can be used to fabricate components for lithium ion batteries. For example, positive electrode materials for lithium batteries typically comprise electroactive materials that can intercalate or react with lithium ions, such as lithium-transition metal oxides or mixed oxides, including LiMn, for example₂O₄、LiCoO₂、LiNiO₂、LiMn_1.5Ni_0.5O₄、LiNi_(1-x-y)Co_xM_yO₂(wherein 0)<x<1、y<1 and M may be Al, Mn, etc.), or one or more phosphate compounds, including, for example, lithium iron phosphate or a mixed lithium manganese iron phosphate. The negative electrode typically includes a lithium intercalation material or an alloy host material. For example, typical electroactive materials used to form the anode include graphite and other forms of carbon, silicon and silicon oxides, tin and tin alloys.

One method of increasing the power of a lithium-ion electrochemical cell is to create a system that includes electrodes having both a high energy capacity electroactive material and a high power capacity electroactive material (e.g., a first positive electrode comprising the high energy capacity electroactive material and a second positive electrode comprising the high power capacity electroactive material). Energy capacity or density is the amount of energy that a battery can store relative to its mass (watt-hours per kilogram (Wh/kg)). Power capacity or density is the amount of power a battery can produce relative to its mass (watts per kilogram (W/kg)). However, in some cases, the mix of different electrode active material chemistries has been limited by voltage range mismatches between the various cathode or anode electroactive materials.

Accordingly, it is desirable to develop hybrid lithium-ion electrochemical cells, particularly for transportation applications, that can successfully use two different electroactive materials regardless of voltage mismatch. In addition, it is desirable that such materials and methods enhance the energy capacity and fast charging capability of lithium ion batteries.

Disclosure of Invention

SUMMARY

This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.

The present disclosure relates to a hybrid lithium-ion electrochemical cell that includes a first electrode having a first polarity and comprising a first electroactive material that reversibly cycles lithium ions. The electrochemical cell also includes a second electrode having a first polarity and comprising a second electroactive material that reversibly cycles lithium ions different from the first electroactive material. At least one third electrode comprises a third electroactive material that reversibly cycles lithium ions and has a second polarity opposite the first polarity. The electrochemical cell includes at least one voltage altering component in electrical communication with a first electrode and a second electrode. The hybrid lithium-ion electrochemical cell has a first operating state corresponding to charging and a second operating state corresponding to discharging. The at least one voltage-varying component is configured to induce a voltage drop in the first operating state or the second operating state.

In one aspect, the at least one voltage-varying component is selected from: diodes, p-n junction diodes, schottky diodes, triodes, transistors, thyristors, field effect transistors, electronic devices comprising p-n junctions, and combinations thereof.

In one aspect, the electrochemical cell further comprises at least two voltage change components in electrical communication with the first electrode and the second electrode. The first voltage changing component is configured to induce a first voltage drop in either the first or second operating state, and the second voltage changing component is configured to allow current to pass in the other of the first or second operating state.

In one aspect, the first and second electrodes are connected in parallel or in series.

In one aspect, the at least one voltage change component further comprises a plurality of voltage change components connected in series such that the voltage drop is a cumulative voltage drop produced by the plurality of voltage change components.

In one aspect, the at least one voltage modification component further comprises a plurality of voltage modification components connected in parallel to reduce resistance.

In one aspect, the voltage drop is greater than 0V and less than or equal to about 5V.

In one aspect, the first electrode is a first positive electrode and the second electrode is a second positive electrode. The first electroactive material is selected from: LiNiMnCoO₂，Li(Ni_xMn_yCo_z)O₂) Wherein x is 0-1, y is 0-1, z is 0-1 and x + y + z = 1, LiNiCoAlO₂，LiNi_1-x-yCo_xAl_yO₂(wherein x is 0. ltoreq. x.ltoreq.1 and y is 0. ltoreq. y.ltoreq.1), LiNi_xMn_1-xO₂(wherein x is not less than 0 and not more than 1), LiMn₂O₄，Li_1+xMO₂(where M is one of Mn, Ni, Co and Al and 0. ltoreq. x.ltoreq.1), LiMn₂O₄(LMO)，LiNi_xMn_1.5O₄，LiV₂(PO₄)₃，LiFeSiO₄，LiMPO₄(wherein M is at least one of Fe, Ni, Co, and Mn), activated carbon, and combinations thereof.

In one aspect, the at least one third electrode is a negative electrode and the third electroactive material is selected from: lithium metal, lithium alloy, silicon (Si), silicon alloy, silicon oxide activated carbon, hard carbon, soft carbon, graphite, graphene, carbon nanotube, lithium titanium oxide (Li)₄Ti₅O₁₂) Tin (Sn), vanadium oxide (V)₂O₅) Titanium dioxide (TiO)₂) Titanium niobium oxide (Ti)_xNb_yO_zWherein x is 0. ltoreq. x.ltoreq.2, y is 0. ltoreq. y.ltoreq.24 and z is 0. ltoreq. z.ltoreq.64), ferrous sulfide (FeS) and combinations thereof.

In one aspect, the second electroactive material is selected from: silicon oxide activated carbon, hard carbon, soft carbon, porous carbon material, graphite, graphene, carbon nanotube, carbon xerogel, mesoporous carbon, template carbon, carbide-derived carbon (CDC), graphene, porous carbon spheres, heteroatom-doped carbon material, metal oxide of noble metal, RuO₂Transition metal, transition metal hydroxide, MnO₂、NiO、Co₃O₄、Co(OH)₂Ni (oh), Polyaniline (PANI), polypyrrole (PPy), polythiophene (PTh), and combinations thereof.

In one aspect, the first electroactive material has a first electrochemical potential and the second electroactive material has a second electrochemical potential. The difference between the second electrochemical potential and the first electrochemical potential defines a first predetermined voltage difference. The voltage drop corresponds to a predetermined voltage difference.

In one aspect, the first electrode is a first negative electrode and the second electrode is a second negative electrode. The first electroactive material is selected from: lithium metal, lithium alloy, silicon (Si), silicon alloy, silicon oxide activated carbon, hard carbon, soft carbon, graphite, graphene, carbon nanotube, lithium titanium oxide (Li)₄Ti₅O₁₂) Tin (Sn), vanadium oxide (V)₂O₅) Titanium dioxide (TiO)₂) Titanium niobium oxide (Ti)_xNb_yO_zWherein x is 0. ltoreq. x.ltoreq.2, y is 0. ltoreq. y.ltoreq.24 and z is 0. ltoreq. z.ltoreq.64), ferrous sulfide (FeS) and combinations thereof. The second electroactive material is selected from: silicon oxide activated carbon, hard carbon, soft carbon, porous carbon material, graphite, graphene, carbon nanotube, carbon xerogel, mesoporous carbon, template carbon, carbide-derived carbon (CDC), graphene, porous carbon spheres, heteroatom-doped carbon material, metal oxide of noble metal, RuO₂Transition metal, transition metal hydroxide, MnO₂、NiO、Co₃O₄、Co(OH)₂、Ni(OH)₂Polyaniline (PANI), polypyrrole (PPy), polythiophene (PTh), and combinations thereof.

In one aspect, the third electrode is a positive electrode and the third electroactive material is selected from: LiNiMnCoO₂，Li(Ni_xMn_yCo_z)O₂) Wherein x is 0-1, y is 0-1, z is 0-1 and x + y + z = 1, LiNiCoAlO₂，LiNi_1-x-yCo_xAl_yO₂(wherein x is 0. ltoreq. x.ltoreq.1 and y is 0. ltoreq. y.ltoreq.1), LiNi_xMn_1-xO₂(wherein x is not less than 0 and not more than 1), LiMn₂O₄，Li_1+xMO₂(where M is one of Mn, Ni, Co and Al and 0. ltoreq. x.ltoreq.1), LiMn₂O₄(LMO)，LiNi_xMn_1.5O₄，LiV₂(PO₄)₃，LiFeSiO₄，LiMPO₄(wherein M is at least one of Fe, Ni, Co, and Mn), activated carbon, and combinations thereof.

The present disclosure also relates to an electrochemical device comprising a plurality of electrochemical cells comprising at least one first electrode having a first polarity and comprising a first electroactive material that reversibly cycles lithium ions. The plurality of electrochemical cells further includes at least one second electrode having a first polarity and comprising a second electroactive material that reversibly cycles lithium ions different from the first electroactive material. The plurality of electrochemical cells further includes at least one third electrode comprising a third electroactive material that reversibly cycles lithium ions and having a second polarity opposite the first polarity. At least two diodes in electrical communication with the first and second electrodes are also provided. The electrochemical device has a first operating state corresponding to charging and a second operating state corresponding to discharging. A first one of the at least two diodes is configured to induce a first voltage drop in a first operating state and a second one of the at least two diodes is configured to allow current to flow in a second operating state. The electrochemical device further includes a housing enclosing the plurality of electrochemical cells.

In one aspect, the plurality of electrochemical cells define: (i) a stack with the at least two diodes arranged inside the stack; or (ii) a stack or cell, and the at least two diodes are arranged outside the stack or cell, but inside the housing.

In one aspect, the first electrode is a first negative electrode and the second electrode is a second negative electrode. The first and second electroactive materials are independently selected from: lithium metal, lithiumAlloy, silicon (Si), silicon alloy, silicon oxide activated carbon, hard carbon, soft carbon, graphite, graphene, carbon nanotube, lithium titanium oxide (Li)₄Ti₅O₁₂) Tin (Sn), vanadium oxide (V)₂O₅) Titanium dioxide (TiO)₂) Titanium niobium oxide (Ti)_xNb_yO_zWherein x is 0. ltoreq. x.ltoreq.2, y is 0. ltoreq. y.ltoreq.24 and z is 0. ltoreq. z.ltoreq.64), ferrous sulfide (FeS) and combinations thereof.

The present disclosure also relates to an electrochemical device comprising a first cell comprising at least one first electrode having a first polarity and comprising a first electroactive material that reversibly cycles lithium ions. A first electrical terminal is connected to the at least one first electrode. The first core cell also has at least one second electrode comprising a second electroactive material that reversibly cycles lithium ions and has a second polarity opposite the first polarity. A second electrical terminal is connected to the at least one second electrode. The electrochemical device also includes a second cell comprising at least one third electrode having a first polarity and comprising a third electroactive material that reversibly cycles lithium ions. A third electrical terminal is connected to the at least one third electrode. At least one fourth electrode has a second polarity and comprises a fourth electroactive material. A fourth electrical terminal is connected to the at least one fourth electrode. The first electrical terminal and the third electrical terminal are electrically connected, and the second electrical terminal and the fourth electrical terminal are electrically connected. At least two voltage change members are in electrical communication with the first electrical terminal and the third electrical terminal. The electrochemical device has a first operating state corresponding to charging and a second operating state corresponding to discharging. A first one of the at least two voltage changing components is configured to induce a voltage drop in a first operating state and a second one of the voltage changing components is configured to allow current to flow in a second operating state.

In one aspect, the second electroactive material and the fourth electroactive material are different, and the electrochemical device further comprises: third and fourth voltage change components in electrical communication with the second and fourth electrical terminals. The third voltage changing component is configured to induce a voltage drop in the first operating state and the fourth voltage changing component is configured to allow current to flow in the second operating state.

Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

Drawings

The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

Fig. 1 shows a schematic of voltage mismatch in a hybrid lithium-ion electrochemical cell comprising a first positive electrode having a first electroactive material, a second positive electrode having a different second electroactive material, and a negative electrode having a negative electroactive material.

Fig. 2A-2C show a simplified schematic design of a hybrid lithium-ion electrochemical cell comprising a first positive electrode having a first electroactive material, a second positive electrode having a different second electroactive material, and a negative electrode having a negative electroactive material with a potential window as depicted in fig. 1. Fig. 2A shows a configuration of a hybrid lithium-ion electrochemical cell, fig. 2B shows the hybrid lithium-ion electrochemical cell during a first operational state of charging, and fig. 2C shows the hybrid lithium-ion electrochemical cell during a second state of discharging.

Fig. 3A-3C show a hybrid lithium-ion electrochemical cell, cycling lithium ions, made according to certain aspects of the present disclosure, including a first positive electrode having a first electroactive material, a second positive electrode having a second, different electroactive material, a negative electrode having a negative electroactive material, and two voltage altering components (e.g., diodes) in electrical communication with the first and second positive electrodes. Fig. 3A shows a configuration of a hybrid lithium-ion electrochemical cell, fig. 3B shows the hybrid lithium-ion electrochemical cell during a first state of operation of charging, and fig. 3C shows the hybrid lithium-ion electrochemical cell during a second state of discharging.

Fig. 4 is a simplified schematic diagram of a p-n heterojunction semiconductor type diode, with the accompanying symbols generally illustrating the operating principle of the diode device.

FIGS. 5A-5B. Fig. 5A shows a schematic of a comparative hybrid lithium-ion electrochemical cell comprising a first positive electrode having a first electroactive material, a second positive electrode having a different second electroactive material, and a negative electrode having a negative electroactive material. Fig. 5B shows the voltage vs. performance of the comparative hybrid lithium-ion electrochemical cell of fig. 5A.

FIGS. 6A-6B. Fig. 6A shows a hybrid lithium-ion electrochemical cell made according to certain aspects of the present disclosure. The hybrid lithium-ion electrochemical cell includes a first positive electrode having a first electroactive material, a second positive electrode having a different second electroactive material, a negative electrode having a negative electroactive material, and two voltage altering components (e.g., diodes) in electrical communication with the first and second positive electrodes. Fig. 6B shows the voltage vs. performance of the hybrid lithium-ion electrochemical cell of fig. 6A.

FIGS. 7A-7B. Fig. 7A shows a variation of a lithium-ion cycled hybrid lithium-ion electrochemical cell in which two different positive electrodes are connected in parallel and in electrical communication with two voltage change components, according to certain aspects of the present disclosure. Fig. 7B shows an electrochemical cell stack comprising a plurality of hybrid lithium-ion electrochemical cells such as those in fig. 7A.

FIGS. 8A-8B. Fig. 8A shows one variation of a lithium-ion cycled hybrid lithium-ion electrochemical cell in which two different positive electrodes are connected in parallel and in electrical communication with two voltage change components, and two different negative electrodes are connected in parallel and in electrical communication with two voltage change components, according to certain aspects of the present disclosure. Fig. 8B shows an electrochemical cell stack comprising a plurality of hybrid lithium-ion electrochemical cells such as those in fig. 8A.

FIGS. 9A-9B. Fig. 9A shows a variation of a lithium-ion cycled hybrid lithium-ion electrochemical cell in which two different positive electrodes are connected in series and in electrical communication with two voltage change components, according to certain aspects of the present disclosure. Fig. 9B shows an electrochemical cell stack including a plurality of hybrid lithium-ion electrochemical cells such as those in fig. 9A.

FIGS. 10A-10B. Fig. 10A shows one variation of a lithium-ion cycled hybrid lithium-ion electrochemical cell in which two different positive electrodes are connected in series and in electrical communication with two voltage change components, and two different negative electrodes are connected in series and in electrical communication with two voltage change components, according to certain aspects of the present disclosure. Fig. 10B shows an electrochemical cell stack including a plurality of hybrid lithium-ion electrochemical cells such as those in fig. 10A.

Fig. 11 shows an electrochemical device including a hybrid lithium-ion electrochemical cell assembly made according to certain variations of the present disclosure, incorporating two different cells having different positive electrodes and voltage altering components.

Fig. 12 shows yet another electrochemical device comprising a hybrid lithium-ion electrochemical cell assembly made according to certain variations of the present disclosure, which incorporates two different cells having different positive and negative electrodes and voltage altering components.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

Detailed Description

Detailed description of the invention

Example embodiments are provided so that this disclosure will be thorough and will fully convey the scope to those skilled in the art. Numerous specific details are set forth such as examples of specific components, parts, devices, and methods to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that should not be construed as limiting the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known techniques have not been described in detail.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" may also be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises," "comprising," "including," and "having" are inclusive and therefore specify the presence of stated features, elements, components, steps, integers, operations, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. While the open-ended term "comprising" should be understood as a non-limiting term used to describe and claim various embodiments set forth herein, in certain aspects the term may instead be understood as a more limiting and limiting term, such as "consisting of …" or "consisting essentially of …. Thus, for any given embodiment of any enumerated component, material, component, element, feature, integer, operation, and/or process step, the present disclosure also specifically includes embodiments that consist of, or consist essentially of, such enumerated component, material, component, element, feature, integer, operation, and/or process step. In the case of "consisting of", alternative embodiments do not include any additional components, materials, components, elements, features, integers, operations and/or process steps, while in the case of "consisting essentially of …", any additional components, materials, components, elements, features, integers, operations and/or process steps that substantially affect the basic and novel characteristics are excluded from such embodiments, but any components, materials, components, elements, features, integers, operations and/or process steps that do not substantially affect the basic and novel characteristics may be included in the embodiments.

Any method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It should also be understood that additional or alternative steps may be employed unless otherwise indicated.

When a component, element, or layer is referred to as being "on," "engaged with," "connected to," or "coupled to" another component, element, or layer, it may be directly on, engaged, connected, or coupled to the other component, element, or layer, or intervening components or layers may be present. In contrast, when an element is referred to as being "directly on," "directly engaged with," "directly connected to" or "directly coupled to" another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements (e.g., "between," directly between, "" adjacent "directly adjacent," etc.) should be interpreted in a similar manner. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Although the terms first, second, third, etc. may be used herein to describe various steps, elements, components, regions, layers and/or sections, these steps, elements, components, regions, layers and/or sections should not be limited by these terms unless otherwise specified. These terms may be only used to distinguish one step, element, component, region, layer or section from another step, element, component, region, layer or section. Terms such as "first," "second," and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first step, element, component, region, layer or section discussed below could be termed a second step, element, component, region, layer or section without departing from the teachings of the example embodiments.

Spatially or temporally relative terms, such as "before", "after", "within", "outside", "below", "above", "upper", etc., may be used herein to simplify the description to describe the relationship of one element or feature to another element(s) or feature(s) as shown in the figures. Spatially and temporally relative terms may be intended to encompass different orientations of the device or system in use or operation in addition to the orientation depicted in the figures.

Throughout this disclosure, numerical values represent approximate measurements or limitations of the ranges, to include minor deviations from the given values and embodiments that approximately have the values and exactly have the values. Other than the working examples provided at the end of the detailed description, all numerical values of parameters (e.g., amounts or conditions) in this specification, including the appended claims, are to be understood as being modified in all instances by the term "about", whether or not "about" actually appears before the numerical value. "about" means that the numerical value allows some slight imprecision (with respect to accuracy; approximately or reasonably close to the value; nearly). As used herein, "about" refers to at least variations that may result from ordinary methods of measuring and using such parameters, provided that the imprecision provided by "about" is not otherwise understood in the ordinary sense. For example, "about" can include variations of less than or equal to 5%, optionally less than or equal to 4%, optionally less than or equal to 3%, optionally less than or equal to 2%, optionally less than or equal to 1%, optionally less than or equal to 0.5%, and optionally in certain aspects less than or equal to 0.1%.

In addition, the disclosure of a range includes all values and disclosures of ranges further divided throughout the range (including the endpoints and subranges given for that range).

Example embodiments will now be described more fully with reference to the accompanying drawings.

The present technology relates to improved electrochemical cells that can be incorporated into energy storage devices, such as lithium ion batteries, which can be used in various applications, such as in vehicles or other transportation applications. However, the present technology may also be used in other electrochemical devices, particularly those that cycle lithium ions, including consumer products. Batteries store electrical energy in chemical compositions or electroactive materials in electrodes having different electrochemical potentials. The difference between the first electrochemical potential of the negative electroactive material in the negative electrode and the second electrochemical potential of the positive electroactive material in the positive electrode determines the battery voltage.

Many lithium-ion electrochemical cells have been designed with high energy capacity and therefore include high energy capacity electroactive materials. However, it may be desirable to have a battery that exhibits not only a high energy capacity (which extends battery capacity to provide extended battery life between charges), but also a high power capacity. The high power capacity may provide a fast discharge or charge capacity. Thus, the power of a lithium-ion electrochemical cell can be increased by including electrodes having different electroactive materials for electrodes having the same polarity, such as a high energy capacity electroactive material and a high power capacity electroactive material.

In certain aspects, a hybrid lithium-ion electrochemical cell may be considered a capacitor assisted battery ("CAB") (e.g., a lithium-ion capacitor mixed with a lithium-ion battery pack in a single cell). Such hybrid electrochemical cells can provide several advantages, such as enhanced power capability compared to lithium ion batteries. For example, an integrated capacitor or supercapacitor may be used to provide current during engine start-up, thereby limiting the current drawn from the lithium ion battery pack during start-up. However, capacitor-assisted systems may experience relatively low energy density and therefore low energy capacity. As described above, in certain aspects, the ability to include different electrode active material chemistries is limited by voltage range mismatches between the various cathode or anode electroactive materials.

Fig. 1 shows a schematic illustrating voltage mismatch in a hybrid lithium-ion electrochemical cell comprising a first positive electrode having a first electroactive material, a second positive electrode having a different second electroactive material, and a negative electrode having a negative electroactive material. In particular, the first electroactive material and the different electroactive materials may be provided as different electrodes within the cell, or may be combined together within a single electrode, for example as different layers.

In fig. 1, a first voltage window 20 is shown for a first positive electroactive material, a second voltage window 22 is shown for a second positive electroactive material, and a third voltage window 24 is shown for a negative electroactive material. The y-axis 30 in fig. 1 represents voltage, while the x-axis 32 represents power. The first voltage window 20 of the first positive electroactive material has a first maximum voltage 34 that is much higher than a second maximum voltage 36 of the second voltage window 22 of the second positive electroactive material. Generally, the first positive electroactive material can generate a significant amount of energy, while the second positive electroactive material can generate a significant amount of power.

Thus, a voltage difference 38 is defined between the first maximum voltage 34 and the second maximum voltage 36. In certain aspects, the second maximum voltage 36 may correspond to an electrochemical potential of the second electroactive material. In other aspects, the second maximum voltage 36 is due to adverse conditions that may occur with the second electroactive material when operating above certain voltages. For example, if the second positive electroactive material exceeds the upper limit of its second maximum voltage 36 during charging, it may potentially suffer structural instability, possible (potential) interactions with the electrolyte and side reactions, and unwanted growth of Solid Electrolyte Interlayers (SEI). Thus, conventionally during charging of a hybrid battery including both a first positive electroactive material having a first maximum voltage 34 and a second positive electroactive material having a second maximum voltage 36, the maximum voltage is limited to the second maximum voltage 36, which limits the potential for achieving full operation (potential) of the first positive electroactive material and generally limits hybrid electrochemical cell design, where matching of electrochemical potentials becomes a design consideration.

Fig. 2A-2C show simplified schematic designs of a lithium-ion electrochemical cell 50 having the voltage potential window depicted in fig. 1. Fig. 2A shows a basic configuration of an electrochemical cell 50 including a first positive electrode 52 and a second positive electrode 54. The first positive electrode 52 is a bi-layer structure that includes a first positive electroactive material in layers formed on each side of a first positive current collector 56. The second positive electrode 54 includes a second positive electroactive material disposed on one side of a second positive current collector 58. As previously described, the first positive electroactive material in the first positive electrode 52 is different from the second positive electroactive material in the second positive electrode 54. The first positive electrode 52 and the second positive electrode 54 are electrically connected in parallel. Two negative electrodes 60 comprising the same negative electroactive material are formed on a negative current collector 62, for example, one as a double layer electrode and one as a single layer electrode. Likewise, the two negative electrodes 60 are connected in parallel with each other.

The lithium-ion electrochemical cell 50 also includes a separator 64 that maintains electrical insulation between the electrodes, but allows ions to flow therethrough. Thus, the separator 64 acts as both an electrical insulator and a mechanical support, as it is sandwiched between electrodes of opposite polarity to prevent physical contact and thus the occurrence of short circuits. The separator 64 is disposed between electrodes of opposite polarity (e.g., between the first positive electrode 52 and the respective negative electrode 60 or between the second positive electrode 54 and the respective negative electrode 60). In addition, the electrochemical cell 50 also includes at least one electrolyte 66, whether in solid or liquid form, to ensure ionic conduction between the electrodes. Where electrolyte 66 is a liquid electrolyte, it may be absorbed within the pores of the membrane of polymer or ceramic separator 64. Where the electrolyte 66 is a solid electrolyte comprising a plurality of electrolyte particles, it may be combined with separator particles to provide a porous layer having the desired electrical insulating properties. For simplicity, fig. 2B-2C do not show electrolyte 66.

Further, the lithium-ion electrochemical cell 50 may include various other components that, although not shown here, are known to those skilled in the art. For example, the lithium-ion electrochemical cell 50 can include a housing, a gasket, a terminal cover, a battery terminal, and any other conventional components or materials that can be located within the electrochemical cell 50 (including between or around the negative electrode 60, the first positive electrode 52, and/or the second positive electrode 54, as non-limiting examples). As previously mentioned, the size and shape of the lithium-ion electrochemical cell 50 may vary depending on the particular application for which it is designed.

Fig. 2B shows the charging process of the lithium-ion electrochemical cell 50. The li-ion electrochemical cell 50 may be recharged or re-powered at any time by applying an external power source (e.g., a charging device) to the electrochemical cell 50 to reverse the electrochemical reactions that occur during battery discharge (as described below). Therefore, lithium ions flow from the first positive electrode 52 and the second positive electrode 54 to the negative electrode 60. The external power source (not shown) that may be used to charge the lithium-ion electrochemical cell 50 may vary depending on the size, configuration, and particular end use of the electrochemical cell 50. Some suitable external power sources include, but are not limited to, ac wall outlets and automotive alternators. The connection of the external power source to the lithium-ion electrochemical cell 50 forces the otherwise non-spontaneous oxidation of lithium at the first positive electrode 52 and/or the second positive electrode 54 to produce electrons and lithium ions. Thus, the electrons flow back to the negative electrode 60 via an external circuit (not shown), while the lithium ions are transported internally through the electrochemical cell 50 (e.g., by the electrolyte across the porous separator) back to the negative electrode 60, where they are recombined to replenish the electroactive material in the negative electrode 60 with lithium for consumption during the next battery discharge cycle. Thus, during battery charging, lithium ions and electrons move from the first positive electrode 52 and the second positive electrode 54 to the negative electrode 60, as indicated by arrows 70 in fig. 2B.

In fig. 2B, during the charging process, the first voltage (V) of the first positive electrode 52₁) Equal to the second voltage (V) of the second positive electrode 54₂). As described in the context of fig. 1, these charging voltages are limited by the highest voltage of the electroactive material having a lower voltage window, e.g., the second maximum voltage 36 of the second voltage window 22 of the second positive electroactive material (e.g., the second positive electrode 54).

Fig. 2C shows the discharge process of the li-ion electrochemical cell 50 during which the li-ion electrochemical cell 50 produces an electric current. The li-ion electrochemical cell 50 generates an electrical current through a reversible electrochemical reaction that occurs when an external circuit is closed (to connect the negative electrode 60 with the first and second positive electrodes 52, 54). In this state, the negative electrode 60 contains a relatively greater amount of recyclable lithium. The chemical potential difference between the first positive electrode 52 and/or the second positive electrode 54 and the negative electrode 60 drives electrons generated by oxidation of lithium (e.g., intercalated lithium) at the negative electrode 60 through an external circuit toward the

positive electrodes

52, 54. At the same time, lithium ions also generated at the negative electrode 60 are transferred toward the

positive electrodes

52, 54 through the electrolyte and separator 64. The electrons flow through the external circuit and lithium ions migrate across the porous separator 64 in the electrolyte to form intercalated or alloyed lithium at the

positive electrode

52, 54. The current through the external circuit may be harnessed and directed through the load device until the intercalated lithium in the negative electrode 60 is depleted and the capacity of the lithium-ion electrochemical cell 50 is reduced.

Thus, the li-ion electrochemical cell 50 can generate an electrical current for a load device, which can be operatively connected to an external electrical circuit. Although the load devices may be any number of known electrically powered devices, some specific examples of electrically powered load devices include motors for hybrid or all-electric vehicles, laptops, tablets, mobile phones, and cordless power tools or appliances as non-limiting examples. The load device may also be a power generation device that charges the li-ion electrochemical cell 50 for the purpose of storing energy. In certain other variations, the electrochemical cell may store energy from a power generating load.

In fig. 2C, during the discharge process, the third voltage (V) of the first positive electrode 52₃) Equal to the fourth voltage (V) of the second positive electrode 54₄). Again as described in the context of fig. 1, these voltages during discharge are limited by a second voltage window 22 corresponding to the second positive cathode 54. Thus, the voltage mismatch between the first voltage window 20 and the second voltage window 22 limits the choice of materials and the design of the electrochemical cell.

According to certain aspects of the present disclosure, a hybrid electrochemical cell, such as a hybrid lithium-ion electrochemical cell like a capacitor-assisted lithium-ion battery, is provided that includes a first electrode and a second electrode, each having the same polarity, and a third electrode having a polarity opposite the first polarity. The battery also includes a separator and an electrolyte. The first electrode comprises a first electroactive material and the second electrode comprises a second electroactive material. In various aspects, the first electrode may be limited in operation by a voltage difference occurring with respect to the second electrode. In certain aspects, the first electroactive material can have a first electrochemical potential and the second electroactive material can have a second, different electrochemical potential. In other aspects, the second electroactive material may be limited to a certain operating voltage, for example, due to undesirable side reactions with the electrolyte, e.g., at high voltages. In this manner, the maximum voltage may be limited during operation of such a hybrid electrochemical cell. In certain variations where the first electrode and the second electrode are positive electrodes, the difference between the first maximum operating voltage of the first electrode and the second maximum operating voltage of the second electrode may be considered a predetermined voltage difference. The third electrode further comprises a third electroactive material. In other variations where the first and second electrodes are negative electrodes, the difference between the first minimum operating voltage of the first electrode and the second minimum operating voltage of the second electrode may be considered a predetermined voltage difference.

The hybrid lithium-ion electrochemical cell also includes at least one voltage altering component. The first electrode, the second electrode and the voltage change member are electrically connected to each other. The at least one voltage change component generates a voltage change (e.g., a voltage drop) that compensates for a voltage mismatch between a first maximum or minimum voltage associated with the first electrode relative to a second maximum or minimum voltage associated with the second electrode during charging or discharging. In certain aspects, the electrochemical cell includes at least two electrical voltage altering components electrically connected to the first electrode and the second electrode, one configured to provide a voltage reduction (or induce a voltage change during charging or discharging), and the other configured to allow current to flow in the other direction (the other of charging or discharging).

For example, fig. 3A-3C show a hybrid lithium-ion electrochemical cell 100 that cycles lithium ions. The hybrid lithium-ion electrochemical cell 100 includes a first electrode 110, such as a first positive electrode, having a first polarity. The first electrode 110 includes a current collector 112. The first electrode 110 further comprises at least one first electroactive material layer 114 comprising a reversible electroactive material layerA first electroactive material that circulates lithium ions. The first electrode may have a potential (V)₁) The first maximum operating voltage indicated. In certain aspects, the first electroactive material can have a first electrochemical potential corresponding to a first maximum operating voltage. As shown, the first electrode 110 is a bi-layer structure having two distinct first electroactive material layers 114 disposed on opposite sides of a current collector 112.

Electrochemical cell 100 also includes a second electrode 120. The second electrode 120 has the same first polarity as the first electrode 110. The second electrode 120 includes a current collector 122. The second electrode 120 further includes a second electroactive material layer 124 comprising a second electroactive material that reversibly circulates lithium ions, the second electroactive material layer having a potential that can be driven by a voltage (V)₂) The second maximum operating voltage indicated. In certain aspects, the second electroactive material may have a second electrochemical potential corresponding to a second maximum operating voltage, although as described above, the second maximum operating voltage may be limited for other reasons. The difference between the second electrochemical potential or the maximum operating voltage and the first electrochemical potential or the maximum operating voltage defines a predetermined voltage difference (av = V)₁ – V₂). In an alternative aspect in which the first and second electrodes are negative electrodes, the difference between the first minimum operating voltage of the first electrode and the second minimum operating voltage of the second electrode may be considered to be a predetermined voltage difference.

Electrochemical cell 100 also includes one or more third electrodes 130. As shown in fig. 3A-3C, the electrochemical cell 100 has two distinct third electrodes 130. Each of the third electrodes 130 has a second polarity opposite to the first polarity of the first and

second electrodes

110 and 120. For example, where the first electrode 110 and the second electrode 120 are positive electrodes, the third electrode 130 is a negative electrode. As further described herein, in other variations, the first electrode 110 and the second electrode 120 may be negative electrodes, and thus the third electrode 130 is a positive electrode. Each third electrode 130 includes a current collector 132. The third electrode 130 further includes at least one third electroactive material layer 134 comprising a third electroactive material that reversibly cycles lithium ions. The third electroactive material can have a third electrochemical potential. As has been shown, the third electrode 130 is a double-layer structure having two different third electroactive material layers 134 disposed on opposite sides of the current collector 132, or a single-layer structure in which the third electroactive material layers 134 are disposed on only one side of the current collector 132.

The hybrid lithium-ion electrochemical cell 100 also includes one or more separators 140 disposed between electrodes of opposite polarity. As shown in fig. 3A-3C, three separators 140 are included, as a non-limiting example. A separator 140 is disposed between the third electrode 130 and the first electrode 110. Another separator 140 is disposed between the first electrode 110 and another third electrode 130. Finally, another separator 140 is disposed between the third electrode 130 and the second electrode 120. The electrochemical cell 100 also includes an electrolyte 142 disposed within or adjacent to the separator 140 and thus between the electrodes facing each other.

In the hybrid lithium-ion electrochemical cell 100, at least one voltage altering component is provided that is in electrical communication with the first electrode 110 and the second electrode 120. As shown in fig. 3A-3C, the first voltage changing component 150 is electrically connected with the first electrode 110 and the second electrode 120, for example, to provide a first direction in which current will flow in a first operating state of the electrochemical cell 100, such as during charging. The second voltage changing component 152 is also electrically connected with the first electrode 110 and the second electrode 120 in a second direction in which current will flow in a second operating state of the electrochemical cell 100, such as during discharge. As will be further described herein, the first voltage varying component 150 is configured to induce a voltage drop (Δ V') corresponding to a predetermined voltage difference (Δ V = V1-V2) in a first operating state, e.g., during charging.

The voltage changing components or devices, such as the first voltage changing component 150 and the second voltage changing component 152, may be any circuit components that facilitate voltage reduction in a desired current direction. In certain aspects, the at least one voltage-varying component may be a diode. Fig. 4 is a simplified schematic diagram of a p-n heterojunction semiconductor type diode 170 with accompanying labels generally illustrating the principle of operation of the diode device. Typically, by way of background, p-n junction diodes are made of semiconductor materials, which may be silicon, germanium, gallium arsenide, and the like. Dopants are added to the semiconductor material to create a region containing negative charge carriers (electrons) on one side (commonly referred to as an n-type semiconductor) and a region containing positive charge carriers (holes) on the opposite side (commonly referred to as a p-type semiconductor). When the n-type and p-type materials are joined and electrically connected, a flow of electrons is generated from the n-type side to the p-type side, which results in a third region between the n-type side and the p-type side in which there are no charge carriers. This is called the depletion region because there are no charge carriers (no electrons and holes). The terminals are attached to the n-type region and the p-type region. The boundary between the n-type region and the p-type region is called the p-n junction, which is where the diode action occurs. When a sufficiently higher potential is applied to the p-type side (anode) than to the n-type side (cathode), electrons flow from the n-type side to the p-type side through the depletion region. However, when the potential is applied in the reverse direction, the p-n junction does not allow electrons to flow in the opposite direction.

Referring again to fig. 4, the diode 170 thus includes an anode 172 defining a first metal contact 174. The diode also includes a doped p-type region 176 in which most holes (+) are present, while a doped n-type region 178 has most electrons (-). The n-type region is adjacent to a second metal contact 180 that defines a cathode 182. Generally, above the threshold voltage of the diode 170, if current is applied in a given direction, a voltage drop may occur in one direction. The amount of voltage drop (Δ V') provided by diode 170 may vary depending on the semiconductor material and dopants used in doped p-type region 176 and doped n-type region 178 and the applied current. As shown in FIG. 4, the first voltage (V) at point 184 may be scaled₁) And a second voltage (V) at point 186₂) A comparison is made, in which Δ V' = V₁–V₂. For example, in p-n diode devices, silicon (Si) incorporated diodes typically exhibit a voltage drop (Δ V') of greater than or equal to about 0.5V to less than or equal to about 0.7V, while germanium (Ge) incorporated diodesThe diode has a voltage drop greater than or equal to about 0.05V to less than or equal to about 0.3V.

A diode is one example of a suitable voltage-varying component. In certain variations, the at least one voltage-altering component is selected from: diodes, p-n junction diodes, schottky diodes, triodes, transistors, thyristors, field effect transistors, electronic devices comprising p-n junctions, and combinations thereof.

In particular, although not shown, voltage changing components or devices, such as the first voltage changing component 150 and the second voltage changing component 152, may be connected in series with each other to provide an accumulated or cumulative voltage drop. For example, if the average voltage drop (Δ V ') of a single diode comprising silicon (Si) is about 0.5V, two such diodes in series provide an average voltage drop (Δ V ') of about 1V, three such diodes in series provide an average voltage drop (Δ V ') of about 1.5V, etc. Thus, when a plurality of voltage altering components are included in an electrochemical cell, which are electrically connected in series with each other and with the first and second electrodes, they may be configured to induce a cumulative voltage drop corresponding to the average voltage drop per device multiplied by the total number of devices connected together (a cumulative voltage drop multiplying an average voltage drop for each device by the number of total devices connected together). In other aspects, although not shown, voltage changing components or devices, such as the first voltage changing component 150 and the second voltage changing component 152, may be connected in parallel with each other to provide an additive or cumulative resistance drop.

As described above, the predetermined voltage difference between the second maximum operating voltage of the second electrode and the first maximum operating voltage of the first electrode can be greater than 0V and less than or equal to about 5V, optionally greater than or equal to about 1V to less than or equal to about 4.5V, and in certain aspects, optionally greater than or equal to about 1.5V to less than or equal to about 4V. Where a plurality of voltage-varying components are provided in electrical communication with the first and second electrodes, the voltage-varying components are configured to induce a cumulative voltage drop corresponding to a predetermined voltage difference (depending on which operating state requires a voltage drop) in either the first or second operating states of the hybrid lithium-ion electrochemical cell.

Referring again to fig. 3B, the hybrid lithium-ion electrochemical cell 100 is in a first operating state corresponding to charging. The first electrode 110 and the second electrode 120 are electrically connected in parallel. During charging, current flows in the direction of arrow 188 from the first electrode 110 and the second electrode 120 (positive electrode) to the third electrode 130 (negative electrode). When the voltage exceeds the threshold voltage of the first voltage change part 150, a current flows therethrough and a voltage drop (Δ V') is generated. As shown in FIG. 3B, the first voltage (V) at point 190 may be adjusted₁) And a second voltage (V) at point 192₂) Comparison is carried out, in which V is present in this operating state₁ = V₂+ Δ V'. In particular, the second voltage changing component 152 is biased such that it does not conduct current in the first operational state of charging. In this way, the first electrode 110 and the second electrode 120 can be successfully charged at a high voltage without a possible overcharge of the second electrode 120 due to the presence of the first voltage changing part 150 providing the necessary voltage drop (Δ V').

In fig. 3C, the hybrid lithium-ion electrochemical cell 100 is in a second operating state corresponding to discharge. During discharge, current flows in the direction of arrow 194 from the third electrode 130 (negative electrode) to the first electrode 110 and the second electrode 120 (positive electrode). When the applied voltage exceeds the threshold voltage of the second voltage change part 152, a current flows therethrough. In certain aspects, the second voltage changing component 152 may be different from the first voltage changing component 150 and have a minimum voltage threshold to ensure that current flows in a desired direction. As shown in FIG. 3C, the third voltage (V) at point 190 may be adjusted₃) And a fourth voltage (V) at point 192₄) A comparison is made, in which V is present in the second operating state₄ = V₃+ Δ V'. In particular, the first voltage changing component 150 is biased such that it does not conduct current in the discharged second operating state, such that current may be generated and distributed to the external load device via a flow path through the second voltage changing component 152.

Fig. 5A-5B and 6A-6B further illustrate the advantages of hybrid lithium-ion electrochemical cells made in accordance with certain aspects of the present disclosure. In fig. 5A, the li-ion electrochemical cell 200 has a first positive electrode 210 comprising lithium manganese nickel manganese oxide LiMn_1.5Ni_0.5O₄A positive electroactive material in the form of (LMNO) having an electrochemical potential (potential relative to Li/Li +) referenced to lithium metal of about 4.75V. The second positive electrode 212 contains a positive electroactive material in the form of activated carbon. Activated carbon does not have an electrochemical potential, but is limited by a maximum operating voltage (potential relative to Li/Li +) referenced to lithium metal of about 4.3V, due to unwanted side reactions with the electrolyte above that voltage. The negative electrode 214 includes lithium titanate (Li)₄Ti₅O₁₂) A negative electrode electroactive material in the form of (LTO). LTO has an electrochemical potential referenced to lithium metal of about 1.55V (potential relative to Li/Li +). The first and second

positive electrodes

210, 212 are electrically connected in parallel. Such a lithium-ion electrochemical cell 200 can be considered a capacitor auxiliary battery because it includes a high power density electroactive material (activated carbon in the second positive electrode 232) to improve the power performance of the high energy density electroactive material (LNMO) in the first positive electrode 230.

Fig. 6A shows a comparative hybrid lithium-ion electrochemical cell, made according to certain aspects of the present disclosure, that includes two voltage altering components. Like the electrochemical cell in fig. 5A, the lithium-ion electrochemical cell 220 in fig. 6A has the same electrode, electroactive material, and electrical connection configuration. Thus, the first positive electrode 230 includes lithium manganese nickel LiMn oxide_1.5Ni_0.5O₄A positive electroactive material in the form of (LMNO). The second positive electrode 232 contains a positive electroactive material in the form of activated carbon. Negative electrode 234 comprises lithium titanate (Li)₄Ti₅O₁₂) A negative electrode electroactive material in the form of (LTO). Again, the first and second

positive electrodes

230, 232 are electrically connected in parallel. In fig. 6A, the electrochemical cell 220 includes both a first voltage changing part 240 and a second voltage changing part 242, which may be diodes, respectively, as shown. First voltage changing part 240 andboth of the second voltage changing parts 242 are electrically connected to the first positive electrode 232 and the second positive electrode 234, but are biased in different directions.

Fig. 5B shows the voltage (y-axis, in volts (V)) versus time (x-axis, in seconds, indicated at 252) performance of the full cell (full cell) lithium-ion electrochemical cell 200 of fig. 5A lacking any voltage altering components. Therefore, only a single voltage trace (voltage trace) 254 is measured. As described above, activated carbon may encounter side reactions with an electrolyte when charged to a potential greater than 4.3V with respect to Li. Due to the voltage mismatch between the LMNO and the AC electroactive materials, the total voltage between the first positive electrode 210 and the second positive electrode 212 is the same during charging and discharging. Fig. 6B similarly shows the voltage (y-axis, labeled 270, in volts (V)) performance over time (x-axis, labeled 272, in seconds) for the lithium-ion electrochemical cell 220 in fig. 6A. In fig. 6B, a first voltage trace 274 is measured for the first positive electrode 230 (LNMO versus LTO) and a second voltage trace 276 is measured for the second positive electrode 232 (activated carbon versus LTO). A voltage difference 278 between the second electrochemical potential of the second positive electrode 232 and the first electrochemical potential of the first positive electrode 230 is also shown.

In fig. 5B, the measured voltage trace 254 includes a first region labeled 260, a second region labeled 262, a third region labeled 264, and a fourth region labeled 266. The battery pack may be charged by both a Constant Current (CC) and a Constant Voltage (CV) process. Thus, the first region 260 is one of Constant Current (CC) charging, while the second region 262 is one of Constant Voltage (CV) charging. The third region 264 indicates the rest period, while the fourth region 266 shows the discharge of the li-ion electrochemical cell 200. In the first region 260, the battery pack is charged to its cutoff voltage by a high constant current, e.g., 3.25V for the LNMO/LTO pair, but the li-ion electrochemical cell/battery pack 200 is only fully charged to about 80 to 90% of its total capacity. In a second region 262, the battery pack is then charged using a lower current by using constant voltage charging. By applying 3.25V to the LNMO/LTO during the constant voltage phase, its current will get smaller until the current meets its requirement of about 0.05 times the constant current. However, as mentioned above, the second positive electrode comprising activated carbon reacts with the electrolyte, so it will always have a current higher than the current requirement. Thus, the Constant Voltage (CV) charging process in the second region 262 does not stop until it reaches the guard time.

Fig. 6B similarly shows a first region labeled 280, a second region labeled 282, a third region labeled 284, and a fourth region labeled 286 of both the first voltage trace 274 and the second voltage trace 276. Again, the first region 280 is one of Constant Current (CC) charging, while the second region 282 is one of Constant Voltage (CV) charging. A third region 284 indicates a rest period, while a fourth region 286 shows the discharge of the li-ion electrochemical cell 220 including both the first voltage altering component 240 and the second voltage altering component 242. The initial portion of the fourth region 286 corresponds to the discharge of the LMNO/LTO first positive electrode 230, while the subsequent portion of the fourth region 286, which shows the voltage difference at the region 288, corresponds to the capacity of the activated carbon/LTO during discharge. In particular, the total cycle time of the lithium-ion electrochemical cell 220 in fig. 6B, fabricated according to certain aspects of the present disclosure, is about 5500 seconds less than the total cycle time of the comparative lithium-ion electrochemical cell 200 in fig. 5B. This is due to the fact that second region 282 of li-ion electrochemical cell 220 in fig. 6B is relatively shorter than second region 262 of li-ion electrochemical cell 200 in fig. 5B. In addition to shorter charge times and shorter overall cycle times, a shorter Constant Voltage (CV) advantageously means less reaction time is available between the activated carbon and the electrolyte in the second positive electrode 232.

Fig. 7A-7B show a variation of a hybrid lithium-ion electrochemical cell that cycles lithium ions. Fig. 7A shows a single hybrid lithium-ion electrochemical cell 300 that includes two different positive electrodes connected in parallel and two voltage altering components made according to certain aspects of the present disclosure. Fig. 7B shows a stack 350 that includes a plurality of hybrid lithium-ion electrochemical cells like those in fig. 7A, with a plurality of different positive electrodes and voltage altering components connected in parallel. In fig. 7A, a hybrid lithium-ion electrochemical cell 300 has a first positive electrode 310 having a first polarity (e.g., positive polarity or cathode). The first positive electrode 310 includes a current collector 312. The first positive electrode 310 is a bi-layer design that includes two first positive electroactive material layers 314 on opposite sides of a current collector 312. Each first positive electrode electroactive material layer 314 includes a first positive electrode electroactive material that reversibly cycles lithium ions. In certain aspects, the first positive electroactive material layer 314 can have a first electrochemical potential.

Electrochemical cell 300 also includes a second positive electrode 320. The second positive electrode 320 has a first polarity as the first positive electrode 310. The second positive electrode 320 includes a current collector 322. The second positive electrode 320 also includes a second positive electroactive material layer 324 that includes a second positive electroactive material that reversibly cycles lithium ions. The second positive electrode 320 can have a second maximum operating voltage, which can be less than the maximum operating voltage of the first positive electrode 310. In certain aspects, the second maximum operating voltage may correspond to a second positive electroactive material having a second electrochemical potential that is different from the electrochemical potential of the first positive electrochemical potential in the first positive electrode 310. Although the design of the second positive electrode 320 in fig. 7A has only a single second positive electroactive material layer 324, it should be noted that although not shown, the electrode could equally be modified to a two-layer design, with two different second positive electroactive material layers 324 disposed on opposite sides of the current collector 322.

The electrochemical cell 300 also includes two third negative electrodes 330 (e.g., anodes) having negative polarity. Each third negative electrode 330 includes a current collector 332. The third negative electrode 330 is a bi-layer design that includes two negative electrode electroactive material layers 334 each containing a reversibly cycling lithium ion and having a third negative electrode electroactive material of a third electrochemical potential. Each distinct third negative electrode electroactive material layer 334 is disposed on an opposite side of the current collector 332.

The hybrid lithium-ion electrochemical cell 300 also includes a plurality of separators 340 disposed between electrodes of opposite polarity. As shown in fig. 7A-7B, three spacers 340 are included as a non-limiting example. A separator 340 is disposed between a third negative electrode 330 and the first positive electrode 310. Another separator 340 is disposed between the first positive electrode 310 and another third negative electrode 330. Finally, another separator 340 is disposed between the third negative electrode 330 and the second positive electrode 320. Electrochemical cell 300 also includes an electrolyte 342 disposed within or adjacent separator 340 and thus between the electrodes facing each other.

In the hybrid lithium-ion electrochemical cell 300, two voltage altering components are provided that are in electrical communication with a first positive electrode 310 and a second positive electrode 320. As shown in fig. 7A-7B, a first voltage-varying component in the form of a first diode 342 is electrically connected to the first positive electrode 310 and the second positive electrode 320, which facilitates current flow in a first direction in a first operating state of the electrochemical cell 300, e.g., during charging. A second voltage changing component in the form of a second diode 344 is also electrically connected to the first positive electrode 310 and the second positive electrode 320. The second diode 344 allows current to flow in a second direction (e.g., opposite the first direction) in a second operating state of the electrochemical cell 300, for example, during discharge. The first positive electrode 310 and the second positive electrode 320 are electrically connected in parallel with each other. In addition, the first and

second diodes

342 and 344 are electrically connected to the first and second

positive electrodes

310 and 320. The first positive electrode 310, the second positive electrode 320, the first diode 342, and the second diode 344 are electrically connected to a positive terminal 346. Each of the third negative electrodes 330 are also connected in parallel with each other, and they are connected to a negative terminal 348.

As described above, in a first operating state corresponding to the hybrid lithium-ion electrochemical cell being charged, the first diode 342 is configured to induce a voltage drop corresponding to a predetermined voltage difference in the first operating state, which generally corresponds to a predetermined voltage difference between a first maximum operating voltage of the first positive electroactive material in the first positive electrode 310 and a second maximum operating voltage of the second positive electroactive material in the second positive electrode 320. In a second operating state, corresponding to a discharge, the second diode 344 allows current to flow in a direction opposite or reversed from the first direction. In certain aspects, the second diode 344 is selected to have a minimum voltage drop that is less than the voltage drop of the first diode 342.

Fig. 7B shows a stack 350 of a plurality of assembled hybrid lithium-ion electrochemical cells like the hybrid lithium-ion electrochemical cell 300 in fig. 7A, with positive electrodes connected in parallel and negative electrodes likewise connected in parallel. For the sake of brevity, the same reference numerals are used in fig. 7B for common components shown in fig. 7A and function in the same manner unless otherwise discussed. Furthermore, for ease of viewing, fig. 7B omits the separator and electrolyte present between the electrodes of opposite polarity in the stack 350.

The stack 350 includes a plurality of first positive electrodes 310 and a plurality of second positive electrodes all electrically connected together in parallel by electrical connections of the first and second

current collectors

312, 322 with a first electrical cable 352, which first electrical cable 352 may include conductive terminals and wires soldered together. The plurality of first positive electrodes 310 and the plurality of second positive electrodes 320 are further in electrical communication and wired with a first diode 342 and a second diode 344, both the first diode 342 and the second diode 344 being electrically connected to a positive terminal 346. As understood by those skilled in the art, the first diode 342 and the second diode 344 may be contained within the stack 350 or outside the stack 350, but electrically connected with suitable electrodes and terminals.

The stack 350 also includes a plurality of third negative electrodes 330 all electrically connected together in parallel by third current collectors 332 to a second electrical cable 354, which second electrical cable 354 may include terminals and conductive leads soldered together. While most of the plurality of third negative electrodes 330 in the stack 350 are double layer electrodes, there are two terminal negative electrodes 356 that include a current collector 332 with a single negative electroactive material layer 334 only on the side facing the opposite electrode (the first positive electrode 310 or the second positive electrode 320).

Although not specifically shown, it will be understood that the hybrid lithium-ion electrochemical cell design as in fig. 7A-7B can be varied to provide a pair of voltage varying devices for two different negative electrodes rather than two different positive electrodes (as in the case of the illustrated hybrid lithium-ion electrochemical cell 300). Thus, the first diode and the second diode may be in electrical communication with a first negative electrode having a first negative electroactive material having a first minimum operating voltage and a different second negative electroactive material having a different second minimum operating voltage defining a predetermined voltage difference, such that the first diode provides a voltage drop corresponding to the predetermined voltage difference in a first operating state of the electrochemical cell corresponding to charging and/or a second operating state corresponding to discharging.

Fig. 8A illustrates another variation of a hybrid lithium-ion electrochemical cell 400 for cycling lithium ions, prepared according to certain aspects of the present disclosure, similar to the variation in fig. 7A. However, in addition to two diodes connected to two different parallel positive electrodes (as in the design of fig. 7A), electrochemical cell 400 in fig. 8A also has two additional voltage-varying components or diodes electrically connected to the negative electrodes. Fig. 8B shows a stack 460 including a plurality of hybrid lithium-ion electrochemical cells, such as those in fig. 8A, having a plurality of different positive electrodes and voltage altering components connected in parallel and a plurality of different negative electrodes and voltage altering components connected in parallel. For simplicity, fig. 8A-8B omit the separator and electrolyte that would be disposed between electrodes of opposite polarity, as understood by those skilled in the art.

In fig. 8A, a hybrid lithium-ion electrochemical cell 400 has a first positive electrode 410, the first positive electrode 410 having a first polarity (e.g., positive polarity or cathode). The first positive electrode 410 includes a current collector 412. The first positive electrode 410 is a bi-layer design that includes two first positive electroactive material layers 414 on opposite sides of a current collector 412. Each first positive electrode electroactive material layer 414 includes a first positive electrode electroactive material that reversibly cycles lithium ions.

The electrochemical cell 400 also includes a second positive electrode 420. The second positive electrode 420 has a first polarity as the first positive electrode 410. The second positive electrode 420 includes a current collector 422. The second positive electrode 420 further includes a second positive electroactive material layer 424 containing a second positive electroactive material that reversibly cycles lithium ions and has a second maximum operating voltage that is less than the first maximum operating voltage of the first positive electroactive material in the first positive electrode 410.

The electrochemical cell 400 also includes a third negative electrode 430 (e.g., an anode) having a negative polarity. The third negative electrode 430 includes a third current collector 432. The third negative electrode 430 is a bi-layer design comprising two first negative electrode electroactive material layers 434, each of the two first negative electrode electroactive material layers 434 containing a first negative electrode electroactive material that reversibly circulates lithium ions and has a third electrochemical potential. The third negative electrode active material layer 434 is disposed on the opposite side of the current collector 432.

In this variation, the electrochemical cell 400 includes two different negative electrodes having different negative electroactive materials. Accordingly, the electrochemical cell 400 further includes a fourth negative electrode 440. The fourth negative electrode 440 has a second polarity as the third negative electrode 430. The fourth negative electrode 440 includes a fourth current collector 442. The fourth negative electrode 440 further includes a second negative electrode electroactive material layer 444, the second negative electrode electroactive material layer 444 comprising a second negative electrode electroactive material that reversibly circulates lithium ions. In certain aspects, the fourth electroactive material has a fourth electrochemical potential that is different from the third electrochemical potential of the first negative electroactive material in the third negative electrode 330.

In the hybrid lithium-ion electrochemical cell 400, four different voltage altering components are provided, a first pair in electrical communication with the first positive electrode 410 and the second positive electrode 420 and a second pair in electrical communication with the third negative electrode 430 and the fourth negative electrode 440. As shown in fig. 8A-8B, a first voltage varying component in the form of a first diode 446 is electrically connected to the first positive electrode 410 and the second positive electrode 420, which facilitates current flow in a first direction in a first operating state of the electrochemical cell 400, such as during charging. A second voltage changing component in the form of a second diode 448 is also electrically connected to the first positive electrode 410 and the second positive electrode 420. The second diode 448 allows current to flow in a second direction (e.g., opposite the first direction) during a second operating state of the electrochemical cell 400, such as during discharge. The first positive electrode 410 and the second positive electrode 420 are electrically connected in parallel with each other. In addition, the first and

second diodes

446 and 448 are electrically connected to the first and second

positive electrodes

410 and 420. The first positive electrode 410, the second positive electrode 420, the first diode 446, and the second diode 448 are electrically connected to the positive terminal 450.

A first predetermined voltage difference is defined between a first maximum operating voltage of the first positive electroactive material of the first positive electrode 410 and a second maximum operating voltage of the second positive electroactive material of the second positive electrode 420. As described above, in the first operating state of the hybrid lithium-ion electrochemical cell 400 corresponding to charging, the first diode 446 is configured to induce a voltage drop corresponding to a first predetermined voltage difference. In a second operating state, corresponding to a discharge, the second diode 448 allows current to flow in a direction opposite or reversed from the first direction.

The third negative electrode 430 and the fourth negative electrode 440 are also electrically connected in parallel with each other and to the negative terminal 452. A third voltage changing component in the form of a third diode 454 is electrically connected to the third negative electrode 430 and the fourth negative electrode 440, which facilitates current flow in the first direction in a second operating state of the electrochemical cell 400, such as during discharge. A third voltage changing component in the form of a fourth diode 456 is also electrically connected to the third negative electrode 430 and the fourth negative electrode 440. The fourth diode 456 allows current to flow in a second direction (e.g., opposite the first direction) during a first operating state of the electrochemical cell 400, such as during charging. The third and

fourth diodes

454 and 456 are electrically connected to the third and fourth

negative electrodes

430 and 440. The third negative electrode 430, the fourth negative electrode 440, the third diode 454, and the fourth diode 456 are electrically connected to the negative terminal 452.

A second predetermined voltage difference is defined between the first minimum operating voltage of the first negative electroactive material of the third negative electrode 430 and the second minimum operating voltage of the second negative electroactive material of the fourth negative electrode 440. As described above, in the second operating state of the hybrid lithium-ion electrochemical cell 400 corresponding to discharge, the third diode 454 is configured to allow current to flow. In a first operating state corresponding to charging, the fourth diode 456 allows current to flow in a direction opposite or reversed to the first direction and induces a voltage drop corresponding to the second predetermined voltage difference.

Fig. 8B shows a stack 460 of a plurality of assembled hybrid lithium-ion electrochemical cells like the hybrid lithium-ion electrochemical cell 400 in fig. 8A, wherein the positive electrodes are different from each other and connected in parallel and the negative electrodes are likewise different from each other and connected in parallel. For the sake of brevity, the same reference numbers are used in fig. 8B for common elements shown in fig. 8A, and function in the same manner unless otherwise discussed. The stack 460 includes a plurality of first positive electrodes 410 and a plurality of second positive electrodes 420 all electrically connected together in parallel by first and second

current collectors

412, 422 to a first cable 442, which first cable 442 may include conductive terminals and wires soldered together. Further, the plurality of first positive electrodes 410 and the plurality of second positive electrodes 420 are in electrical communication and wiring with first and

second diodes

446 and 448, which in turn are in electrical communication with a positive terminal 450. As understood by those skilled in the art, the first diode 446 and the second diode 448 may be included within the stack 460 or external to the stack 460, but electrically connected with suitable electrodes and terminals.

The stack 460 also includes a plurality of third negative electrodes 430 and a plurality of fourth negative electrodes 440 all electrically connected together in parallel by third and fourth

current collectors

432, 442 with a second electrical cable 462, which second electrical cable 462 may be a conductive wire soldered together. Further, the plurality of third negative electrodes 430 and the plurality of fourth negative electrodes 440 are in electrical communication and wired with third diodes 454 and fourth diodes 456, all of which are in electrical communication with the negative terminal 452. As understood by those skilled in the art, the first diode 446 and the second diode 448 may be included within the stack 460 or external to the stack 460, but electrically connected with suitable electrodes and terminals. As understood by those skilled in the art, the third diode 454 and the fourth diode 456 may be included within the stack 460 or outside the stack 460, but electrically connected with suitable electrodes and terminals. While most of the plurality of third negative electrodes 430 in the stack 460 are double layer electrodes, there is an end third negative electrode 470 that includes a current collector 472 having a single first negative electrode electroactive material layer 474 only on the side facing the opposite electrode (second positive electrode 420). There is also an end fourth negative electrode 480 that includes a current collector 482 with a single second negative electroactive material layer 484 only on the side facing the opposite electrode (first positive electrode 410). The stack 460 has a plurality of assembled hybrid lithium-ion electrochemical cells having positive electrodes in parallel and negative electrodes in parallel. In this manner, the stack 460 also includes a voltage change component that compensates not only for a first predetermined voltage difference corresponding to a maximum operating voltage difference for different positive electroactive materials in different positive electrodes, but also for a second predetermined voltage difference corresponding to a minimum operating voltage difference for different negative electroactive materials in different negative electrodes.

Fig. 9A-9B illustrate another variation of a hybrid lithium-ion electrochemical cell that cycles lithium ions. Fig. 9A illustrates a single hybrid lithium-ion electrochemical cell 500 made according to certain aspects of the present disclosure, which includes two distinct positive electrodes connected in series and two voltage-varying components. Fig. 9B shows a stack 550 including a plurality of hybrid lithium-ion electrochemical cells, such as those in fig. 9A, with a plurality of different positive electrodes and voltage altering components connected in series. In fig. 9A, the hybrid lithium-ion electrochemical cell 500 has a first positive electrode 510, the first positive electrode 510 having a first polarity (e.g., positive polarity or cathode). The first positive electrode 510 includes a current collector 512. The first positive electrode 510 is a bi-layer design that includes two first positive electroactive material layers 514 on opposite sides of the current collector 512. Each first positive electroactive material layer 514 includes a first positive electroactive material that reversibly cycles lithium ions and has a first maximum operating voltage.

The electrochemical cell 500 also includes a second positive electrode 520. The second positive electrode 520 has a first polarity as the first positive electrode 510. The second positive electrode 520 includes a current collector 522. The second positive electrode 520 further includes a second positive electroactive material layer 524, the second positive electroactive material layer 524 comprising a second positive electroactive material that reversibly cycles lithium ions and has a second maximum operating voltage different from the first maximum operating voltage of the first positive electroactive material in the first positive electrode 510. Although the design in fig. 9A has only a single second positive electroactive material layer 524, it should be noted that although not shown, the electrode could equally be modified to a bi-layer design, where two different second positive electroactive material layers 524 are disposed on opposite sides of the current collector 522.

The electrochemical cell 500 also includes two third negative electrodes 530 (e.g., anodes) having negative polarity. Each third negative electrode 530 includes a current collector 532. The third negative electrode 530 may be a bi-layer design including two negative electrode electroactive material layers 534, the two negative electrode electroactive material layers 534 each containing a third negative electrode electroactive material that reversibly circulates lithium ions and has a third electrochemical potential. Each different third negative electrode electroactive material layer 534 is disposed on a single side or opposite side of the current collector 532. In the electrochemical cell 500, each of the third negative electrodes 530 is connected in parallel. Furthermore, fig. 9A-9B omit for ease of viewing, separators and electrolytes present in the stack 550 between electrodes of opposite polarity as previously shown, for example, in fig. 3A and 7A.

In the hybrid lithium-ion electrochemical cell 500, two voltage altering components are provided in electrical communication with a first positive electrode 510 and a second positive electrode 520. As shown in fig. 9A-9B, a first voltage changing component in the form of a first diode 542 is electrically connected to the first positive electrode 510 and the second positive electrode 520 that facilitates current flow in a first direction during a second operating state, e.g., discharge, of the electrochemical cell 500. A second voltage changing component in the form of a second diode 544 is also electrically connected to the first positive electrode 510 and the second positive electrode 520. The second diode 544 allows current to flow in a second direction (e.g., opposite the first direction) during a first operating state of the electrochemical cell 500, such as during charging.

The first positive electrode 510 and the second positive electrode 520 are electrically connected in series with each other. In addition, the first and

second diodes

542 and 544 are electrically connected to the first and second

positive electrodes

510 and 520. More specifically, the first diode 542 is arranged between the first positive electrode 510 and the second positive electrode 520 connected in series. Likewise, the second diode 544 is arranged between the first positive electrode 510 and the second positive electrode 520, which are connected in series with each other. The first positive electrode 510, the second positive electrode 520, the first diode 542, and the second diode 544 are electrically connected to the positive terminal 546. Each of the third negative electrodes 530 are also electrically connected in parallel with each other and further connected to a negative terminal 548.

As described above, in a first operating state corresponding to the hybrid lithium-ion electrochemical cell being charged, the second diode 544 is configured to induce a voltage drop corresponding to a predetermined voltage difference in a second operating state, which generally corresponds to a predetermined voltage difference between a first maximum operating voltage of the first positive electroactive material in the first positive electrode 510 and a second maximum operating voltage of the second positive electroactive material in the second positive electrode 520. In a second operating state, corresponding to a discharge, the first diode 542 allows current to flow in a direction opposite or reversed to the first direction.

Fig. 9B shows a stack 550 of a plurality of assembled hybrid lithium-ion electrochemical cells like the hybrid lithium-ion electrochemical cell 300 in fig. 9A, with positive electrodes connected in series and negative electrodes connected in parallel. For the sake of brevity, the same reference numbers are used in fig. 9B for common elements shown in fig. 9A and function in the same manner unless otherwise discussed. Furthermore, for ease of viewing, fig. 9B omits the separator and electrolyte present between the electrodes of opposite polarity in the stack 550.

The stack 550 includes a plurality of first positive electrodes 510 and a plurality of second positive electrodes 520 all electrically connected together in series by electrical connections of the first and second

current collectors

512, 522 with a first cable 552, which first cable 552 may include conductive terminals and wires soldered together. The plurality of first positive electrodes 510 and the plurality of second positive electrodes 520 are further in electrical communication with and wired to a first diode 542 and a second diode 544, both of which are electrically connected to a positive terminal 546. As understood by those skilled in the art, the first diode 542 and the second diode 544 may be included within the stack 550 or external to the stack 550, but electrically connected with suitable electrodes and terminals.

The stack 550 also includes a plurality of third negative electrodes 530 that are all electrically connected together in series by third current collectors 532 to a second electrical cable 554, which second electrical cable 554 may include terminals and electrically conductive leads that are soldered together. While most of the plurality of third negative electrodes 530 in the stack 550 are double layer electrodes, there are two terminal negative electrodes 556 that include a current collector 532 with a single negative electroactive material layer 534 only on the side facing the opposite electrode (first positive electrode 510 or second positive electrode 520).

Although not specifically shown, it will be understood that the design of a hybrid lithium-ion electrochemical cell as in fig. 9A-9B can be varied to provide a pair of voltage altering devices for two different negative electrodes rather than two different positive electrodes (as in the case of the illustrated hybrid lithium-ion electrochemical cell 500). Thus, the first diode and the second diode may be in electrical communication with a first negative electrode having a first negative electroactive material having a first minimum operating voltage and a second negative electroactive material having a second minimum operating voltage defining a predetermined voltage difference, such that the first diode and/or the second diode provides a voltage drop corresponding to the predetermined voltage difference in a first operating state of the electrochemical cell corresponding to charging and/or a second operating state corresponding to discharging. The first negative electrode and the second negative electrode may be electrically connected in series.

Fig. 10A illustrates another variation of a hybrid lithium-ion electrochemical cell 600 that cycles lithium ions, prepared according to certain aspects of the present disclosure, similar to the variation in fig. 9A. However, in addition to two diodes connected to two different positive electrodes in series (as in the design of fig. 9A), electrochemical cell 600 in fig. 10A also has two additional voltage-varying components or diodes electrically connected to the negative electrodes that are also connected in series. Thus, fig. 10B shows a stack 660 including a plurality of hybrid lithium-ion electrochemical cells, such as those in fig. 10A, having a plurality of different positive electrodes and voltage altering components connected in series and a plurality of different negative electrodes and voltage altering components connected in series. For simplicity, fig. 10A-10B omit the separator and electrolyte that would be disposed between electrodes of opposite polarity, as understood by those skilled in the art.

In fig. 10A, a hybrid lithium-ion electrochemical cell 600 has a first positive electrode 610, the first positive electrode 610 having a first polarity (e.g., positive polarity or cathode). The first positive electrode 610 includes a current collector 612. The first positive electrode 610 is a bi-layer design that includes two first positive electroactive material layers 614 on opposite sides of a current collector 612. Each first positive electroactive material layer 614 includes a first positive electroactive material that reversibly cycles lithium ions and has a first maximum operating voltage.

The electrochemical cell 600 also includes a second positive electrode 620. The second positive electrode 620 has a first polarity as the first positive electrode 610. The second positive electrode 620 includes a current collector 622. The second positive electrode 620 further includes a second positive electroactive material layer 624 including a second positive electroactive material that reversibly cycles lithium ions and has a second maximum operating voltage different from the first maximum operating voltage of the first positive electroactive material in the first positive electrode 610.

The electrochemical cell 600 also includes a third negative electrode 630 (e.g., an anode) having an opposite or negative polarity. The third negative electrode 630 includes a third current collector 632. The third negative electrode 630 is a bi-layer design comprising two first negative electrode electroactive material layers 634, each of the two first negative electrode electroactive material layers 634 comprising a first negative electrode electroactive material that reversibly circulates lithium ions and has a first minimum operating voltage. The third negative electrode active material layer 634 is disposed on the opposite side of the current collector 632.

In this variation, the electrochemical cell 600 includes two different negative electrodes having different negative electroactive materials with different minimum operating voltages. Accordingly, the electrochemical cell 600 further includes a fourth negative electrode 640. The fourth negative electrode 640 has the second polarity as the third negative electrode 630. The fourth negative electrode 640 includes a fourth current collector 642. The fourth negative electrode 640 further comprises a second negative electrode electroactive material layer 644 comprising a second negative electrode electroactive material that reversibly circulates lithium ions and has a second minimum operating voltage different from the first minimum operating voltage of the first negative electrode electroactive material in the third negative electrode 630.

In the hybrid lithium-ion electrochemical cell 600, four different voltage altering components are provided, a first pair in electrical communication with the first positive electrode 610 and the second positive electrode 620 and a second pair in electrical communication with the third negative electrode 630 and the fourth negative electrode 640. As shown in fig. 10A-10B, a first voltage changing component in the form of a first diode 646 is electrically connected to the first positive electrode 610 and the second positive electrode 620, which facilitates current flow in a first direction during a second operating state, e.g., discharge, of the electrochemical cell 600. A second voltage changing component in the form of a second diode 648 is also electrically connected to the first positive electrode 610 and the second positive electrode 620. The second diode 648 allows current to flow in a second direction (e.g., reversed from the first direction) during a first operating state of the electrochemical cell 600, such as during charging. The first positive electrode 610 and the second positive electrode 620 are electrically connected in series with each other. In addition, the first and

second diodes

646 and 648 are electrically connected to the first and second

positive electrodes

610 and 620. More specifically, the first diode 646 is disposed between the first positive electrode 610 and the second positive electrode 620 connected in series. Likewise, the second diode 648 is disposed between the first positive electrode 610 and the second positive electrode 620 that are connected in series with each other. The first positive electrode 610, the second positive electrode 620, the first diode 646, and the second diode 648 are electrically connected to the positive terminal 650.

A first predetermined voltage difference is defined between a first maximum operating voltage of the first positive electroactive material of the first positive electrode 610 and a second maximum operating voltage of the second positive electroactive material of the second positive electrode 620. As described above, in a first operating state corresponding to the charged hybrid lithium-ion electrochemical cell 600, the second diode 648 is configured to induce a voltage drop corresponding to a first predetermined voltage difference. In a second operating state, corresponding to a discharge, the first diode 646 allows current to flow in a direction opposite or reversed from the first direction.

The third negative electrode 630 and the fourth negative electrode 640 are also electrically connected in series with each other and to the negative terminal 652. A third voltage changing component in the form of a third diode 654 is electrically connected to the third negative electrode 630 and the fourth negative electrode 640 to facilitate current flow in the first direction in a second operating state of the electrochemical cell 600, such as during discharge. A fourth voltage changing component in the form of a fourth diode 656 is also electrically connected to the third negative electrode 630 and the fourth negative electrode 640. The fourth diode 656 allows current to flow in a second direction (e.g., reversed from the first direction) during a first operating state of the electrochemical cell 600, such as during charging. The third diode 654 and the fourth diode 656 are electrically connected to the third negative electrode 630 and the fourth negative electrode 640. More specifically, the third diode 654 is disposed between the first positive electrode 610 and the second positive electrode 620 connected in series. Likewise, a fourth diode 656 is disposed between the first positive electrode 610 and the second positive electrode 620, which are connected in series with each other. The third negative electrode 630, the fourth negative electrode 640, the third diode 654, and the fourth diode 656 are electrically connected to the negative terminal 652.

A second predetermined voltage difference is defined between a first minimum operating voltage of the first negative electroactive material of the third negative electrode 630 and a second minimum operating voltage of the second negative electroactive material of the fourth negative electrode 640. As described above, in the first operating state corresponding to the charged hybrid lithium-ion electrochemical cell 600, the fourth diode 656 is configured to induce a voltage drop corresponding to the second predetermined voltage difference. In a second operating state of the hybrid lithium-ion electrochemical cell 600, which corresponds to discharging, the third diode 654 allows current to flow.

Fig. 10B shows a stack 660 of a plurality of assembled hybrid lithium-ion electrochemical cells like the hybrid lithium-ion electrochemical cell 600 in fig. 10A, with the positive electrodes being different from each other and connected in series and the negative electrodes likewise being different from each other and connected in series. For the sake of brevity, the same reference numbers are used in fig. 10B for common elements shown in fig. 10A, and function in the same manner unless otherwise discussed. The stack 660 includes a plurality of first positive electrodes 610 and a plurality of second positive electrodes 620 all electrically connected together in series by first and second

current collectors

612, 622 to a first cable 642, which first cable 642 may include conductive terminals and wires soldered together. Further, the plurality of first positive electrodes 610 and the plurality of second positive electrodes 620 are in electrical communication and wiring with first and

second diodes

646, 648, which in turn are in electrical communication with a positive terminal 650. As understood by those skilled in the art, the first diode 646 and the second diode 648 may be included within the stack 660 or outside the stack 660, but electrically connected with suitable electrodes and terminals.

The stack 660 also includes a plurality of third negative electrodes 630 and a plurality of fourth negative electrodes 640 that are all electrically connected together in series by third and fourth

current collectors

632, 642 with a second electrical cable 662, which second electrical cable 662 may be electrically conductive wires that are soldered together. Further, the plurality of third negative electrodes 630 and the plurality of fourth negative electrodes 640 are in electrical communication and wiring with third diodes 654 and fourth diodes 656, all of which are in electrical communication with a negative terminal 652. As understood by those skilled in the art, the third diode 654 and the fourth diode 656 may be included within the stack 660 or external to the stack 660, but electrically connected with appropriate electrodes and terminals. While a majority of the plurality of third negative electrodes 630 in the stack 660 are double layer electrodes, there is an end third negative electrode 670, the end third negative electrode 670 including a current collector 672 having a single first negative electroactive material layer 674 only on the side facing the opposite electrode (second positive electrode 620). The terminal fourth negative electrode 680 includes a current collector 682 having a single second negative electroactive material layer 684 only on the side facing the opposite electrode (first positive electrode 610). Stack 660 has a plurality of assembled hybrid lithium-ion electrochemical cells having positive electrodes in series and negative electrodes in series. In this manner, the stack 660 also includes a voltage change component that compensates not only for the first predetermined voltage difference corresponding to the maximum operating voltage difference for different positive electroactive materials in different positive electrodes, but also for the minimum operating voltage corresponding to the electrochemical potential difference for different negative electroactive materials in different negative electrodes.

Fig. 11 illustrates yet another variation of an electrochemical device 700 comprising a hybrid lithium-ion electrochemical cell assembly made according to certain variations of the present disclosure incorporating two different cells with different positive electrodes. The first cell 710 includes a plurality of lithium-ion electrochemical cells defining a plurality of negative electrodes, a plurality of first positive electrodes, a separator, and having an electrolyte, etc. As shown, the battery core 710 has a jellyroll (jellyroll) configuration, although the battery core may also be manufactured by stacking (winding stacking, etc., as previously described). In this design, the first cell 710 has a first positive electrode with a first positive electrochemical material having a first maximum operating voltage. The plurality of internal positive electrodes are electrically connected to the first positive terminal 720. The first cell 710 also has a negative electrode that contains a negative electroactive material. The plurality of internal negative terminals are electrically connected to the first negative terminal 722.

The second cell 730 includes a plurality of lithium-ion electrochemical cells defining a plurality of negative electrodes, a plurality of second positive electrodes, a separator, and having an electrolyte, etc. As shown, the cell 730 has a jellyroll configuration, although other configurations are equally possible. Second cell 730 has a second positive electrode with a second positive electrochemical material having a second maximum operating voltage. The first maximum operating voltage of the first anodal electroactive material and the second maximum operating voltage of the second anodal electroactive material define a predetermined voltage difference. The plurality of inner second positive electrodes are electrically connected to the second positive terminal 740. The second cell 730 also has a negative electrode that includes the same negative electroactive material as the negative electrode in the first cell 710. The plurality of internal negative terminals are electrically connected to the second negative terminal 742. The first and second

positive terminals

720 and 740 are electrically connected to each other. In addition, the first negative terminal 722 and the second negative terminal 742 are electrically connected to each other.

Outside of the first cell 710 and the second cell 730 is a first voltage changing part in the form of a first diode 744. The first diode 744 is electrically connected to the first cathode terminal 720 and the second cathode terminal 740. The first diode 744 facilitates current flow in a first direction during a second operating state of the electrochemical device 700, such as during discharge. A second voltage changing component in the form of a second diode 746 is also electrically connected to said first cathode terminal 720 and second cathode terminal 740. The second diode 746 allows current to flow in a second direction (e.g., reversed from the first direction) in a first operating state of the electrochemical device 700, such as during charging. As described above, in the first operating state of the electrochemical device 700 corresponding to charging, the second diode 746 is configured to induce a voltage drop corresponding to a predetermined voltage difference between the positive electrochemical materials. In a second operating state corresponding to a discharge, the first diode 744 allows current to flow in a direction opposite or reversed to the first direction.

Fig. 12 illustrates yet another variation of an electrochemical device 800 comprising a hybrid lithium-ion electrochemical cell assembly made according to certain variations of the present disclosure incorporating two different cells with different positive electrodes and different negative electrodes. First cell 810 includes a plurality of lithium-ion electrochemical cells defining a plurality of first positive electrodes, a plurality of first negative electrodes, a separator, and having an electrolyte, etc. As shown, the battery cell 810 has a roll core configuration, although the battery cell may also be manufactured by stacking, winding stacking, or the like. The first cell 810 has a first positive electrode with a first positive electrochemical material having a first maximum operating voltage. The plurality of internal positive electrodes are electrically connected to the first positive terminal 820. The first cell 810 also has a first negative electrode comprising a first negative electroactive material. The first negative electrode electroactive material has a first minimum operating voltage. The plurality of inner first negative electrodes are electrically connected to the second negative terminal 822.

Second cell 830 includes a plurality of lithium-ion electrochemical cells defining a plurality of second negative electrodes, a plurality of second positive electrodes, a separator, and having an electrolyte, etc. Again, the cell core 830 has a representative roll core configuration, although other designs are possible. Second cell 830 has a second positive electrode with a second positive electrochemical material having a second maximum operating voltage. The first maximum operating voltage of the first anodal electroactive material and the second maximum operating voltage of the second anodal electroactive material define a first predetermined voltage difference. The plurality of inner second positive electrodes are electrically connected to the second positive terminal 840. The second cell 830 also has a second negative electrode comprising a second negative electroactive material having a second minimum operating voltage. The first minimum operating voltage of the first negative electrode electroactive material and the second minimum operating voltage of the second negative electrode electroactive material define a second predetermined voltage difference. The plurality of inner second negative electrodes are electrically connected to the second negative terminal 842. The first and second

positive terminals

820 and 840 are electrically connected to each other. In addition, the first and second

negative terminals

822 and 842 are electrically connected to each other.

Outside first cell 810 and second cell 830 is a first voltage changing component in the form of a first diode 844. The first diode 844 is electrically connected to the first positive terminal 820 and the second positive terminal 840. The first diode 844 facilitates current flow in a first direction during a first operating state of the electrochemical device 800, such as during charging. A second voltage modification component in the form of a second diode 846 is also electrically connected to the first cathode terminal 820 and the second cathode terminal 840. The second diode 846 allows current to flow in a second direction (e.g., reverse the first direction) in a second operating state of the electrochemical device 800, such as during discharge. As described above, in a first operating state of the electrochemical device 800 corresponding to charging, the first diode 844 is configured to induce a voltage drop corresponding to a first predetermined voltage difference between the positive electrochemical materials. In a second operating state, corresponding to a discharge, second diode 846 allows current to flow in a direction opposite or reversed to the first direction.

Also included is a third voltage changing component in the form of a third diode 848. The third diode 848 is electrically connected to the first and

second anode terminals

822, 842. The third diode 848 facilitates current flow in a first direction during a first operating state of the electrochemical device 800, such as during charging. A second voltage change component in the form of a fourth diode 850 is also electrically connected to the first and

second anode terminals

822, 842. The fourth diode 850 allows current to flow in a second direction (e.g., reverse to the first direction) in a second operating state of the electrochemical device 800, such as during discharge. As described above, in the first operating state of the electrochemical device 800 corresponding to a discharge, the third diode 848 is configured to induce a voltage drop corresponding to a second predetermined voltage difference between the negative electrochemical materials. In a second operating state, corresponding to a discharge, fourth diode 850 allows current to flow in a direction opposite or reversed from the first direction.

In this way, a lithium-ion electrochemical device, especially for transport applications, is provided that incorporates a hybrid lithium-ion electrochemical cell having at least two different electroactive materials, regardless of voltage mismatch.

Various components of the lithium-ion electrochemical cell are further described herein. As described above, a typical lithium ion battery includes a negative electrode, a positive electrode, and a porous separator (e.g., a microporous or nanoporous polymeric separator) disposed between the two electrodes. A negative electrode current collector may be disposed at or near the negative electrode, and a positive electrode current collector may be disposed at or near the positive electrode. The negative and positive electrode current collectors may be coated on one or both sides, as is known in the art. In certain aspects, the current collector may be coated with active material/electrode layers on both sides. As previously described, the negative and positive electrode current collectors collect and move free electrons to or from, respectively, an interruptible external circuit that connects a load to the negative (through its current collector) and positive (through its current collector).

The porous separator includes an electrolyte, which may also be present in the negative electrode and the positive electrode. Any suitable electrolyte capable of conducting lithium ions between the negative electrode and the positive electrode, whether in solid form or in solutionCan be used in the lithium ion battery pack. In certain aspects, the electrolyte may be a non-aqueous liquid electrolyte solution comprising a lithium salt dissolved in an organic solvent or a mixture of organic solvents. Numerous conventional nonaqueous liquid electrolyte solutions can be used in the lithium ion batteries. A non-limiting list of lithium salts that may be dissolved in an organic solvent to form the non-aqueous liquid electrolyte solution includes: lithium hexafluorophosphate (LiPF)₆) Lithium perchlorate (LiClO)₄) Lithium aluminum tetrachloride (LiAlCl)₄) Lithium iodide (LiI), lithium bromide (LiBr), lithium thiocyanate (LiSCN), and lithium tetrafluoroborate (LiBF)₄) Lithium tetraphenylborate (LiB (C)₆H₅)₄) Lithium bis (oxalato) borate (LiB (C)₂O₄)₂) (LiBOB) lithium hexafluoroarsenate (LiAsF)₆) Lithium trifluoromethanesulfonate (LiCF)₃SO₃) Bis (trifluoromethanesulfonylimide) (LiN (CF)₃SO₂)₂) Lithium fluorosulfonylimide (LiN (FSO)₂)₂) And combinations thereof.

These lithium salts may be dissolved in a variety of organic solvents, including, but not limited to, various alkyl carbonates, such as cyclic carbonates (e.g., Ethylene Carbonate (EC), Propylene Carbonate (PC), Butylene Carbonate (BC)), linear carbonates (e.g., dimethyl carbonate (DMC), diethyl carbonate (DEC), ethylmethyl carbonate (EMC)), aliphatic carboxylic acid esters (e.g., methyl formate, methyl acetate, methyl propionate), γ -lactones (e.g., γ -butyrolactone, γ -valerolactone), chain structural ethers (e.g., 1, 2-dimethoxyethane, 1, 2-diethoxyethane, ethoxymethoxyethane), cyclic ethers (e.g., tetrahydrofuran, 2-methyltetrahydrofuran), and combinations thereof.

In other variations, a solid electrolyte may be used. This includes solid polymer electrolytes that conduct lithium ions as well as solid ceramic-based electrolytes. In certain solid electrolyte designs, a separate separator member or adhesive may not be required in the electrochemical cell. In designs with liquid electrolytes, the electrochemical cell includes a separator structure.

The porous separator functions as both an electrical insulator and a mechanical support by being interposed between each negative and positive electrode to prevent physical contact and thus the occurrence of short circuits. In addition to providing a physical barrier between the electrodes, the porous separator can provide a path of least resistance for internal passage of lithium ions (and associated anions) during lithium ion cycling to facilitate functioning of the lithium ion battery.

In certain instances, the porous separator can include microporous polymeric separators including those made from homopolymers (derived from a single monomeric component) or heteropolymers (derived from more than one monomeric component) that include a polyolefin, which can be linear or branched. In certain aspects, the polyolefin may be Polyethylene (PE), polypropylene (PP), or a blend of PE and PP, or a porous film of a multilayer structure of PE and/or PP. Commercially available polyolefin porous separator membranes include Celgard available from Celgard llc^®2500 (single layer polypropylene separator) and CELGARD^®2320 (three layer polypropylene/polyethylene/polypropylene separator).

When the porous separator is a microporous polymeric separator, it can be a single layer or a multi-layer laminate. For example, in one embodiment, a single layer of the polyolefin can form the entire microporous polymeric separator. In other aspects, the separator can be a fibrous membrane having a large number of pores extending between opposing surfaces and can have a thickness of, for example, less than 1 millimeter. However, as another example, a plurality of discrete layers of similar or dissimilar polyolefins may be assembled to form the microporous polymeric separator. Instead of or in addition to the polyolefin, the microporous polymeric separator may also include other polymers such as, but not limited to, polyethylene terephthalate (PET), polyvinylidene fluoride (PVdF), polyamide (nylon), polyurethane, polycarbonate, polyester, Polyetheretherketone (PEEK), Polyethersulfone (PES), Polyimide (PI), polyamide-imide, polyether, polyoxymethylene (e.g., acetal), polybutylene terephthalate, polyethylene naphthenate, polybutylene, polymethylpentene, polyolefin copolymers, acrylonitrile-butadiene-styrene copolymers (ABS), polystyrene copolymers, polymethacryleneMethyl Acrylate (PMMA), polysiloxane polymers (e.g. Polydimethylsiloxane (PDMS)), Polybenzimidazole (PBI), Polybenzoxazole (PBO), polyphenylene, polyarylene ether ketone, polyperfluorocyclobutane, polyvinylidene fluoride copolymers (e.g. PVdF-hexafluoropropylene or (PVdF-HFP)) and polyvinylidene fluoride terpolymers, polyvinyl fluoride, liquid crystal polymers (e.g. VECTRAN @)^TM(Hoechst AG, Germany) and ZENITE (DuPont, Wilmington, Germany)), aramid, polyphenylene ether, cellulosic material, mesoporous silica and/or combinations thereof.

Further, the porous separator may be mixed with a ceramic material or a surface of the porous separator may be coated with a ceramic material. For example, the ceramic coating may include alumina (Al)₂O₃) Silicon dioxide (SiO)₂) Or a combination thereof. Various conventionally available polymers and commercial products for forming the separator are contemplated, as well as numerous manufacturing processes that may be used to produce such microporous polymeric separators.

In certain aspects, the positive electrode can be formed of a lithium-based active material that can sufficiently undergo lithium intercalation and deintercalation, absorption and desorption, or alloying and dealloying, while serving as a positive terminal of the lithium ion battery. The positive electrode can include a polymeric binder material to structurally reinforce the lithium-based active material. The positive electrode electroactive material can include one or more transition metals, such as manganese (Mn), nickel (Ni), cobalt (Co), chromium (Cr), iron (Fe), vanadium (V), and combinations thereof.

In certain variations, the one or more positive electrodes may comprise a positive electroactive material that is a high energy capacity electroactive material. The one or more second positive electrodes can optionally include a high power capacity electroactive material. In other variations, the second positive electrode may comprise a different layer of high energy capacity electroactive material. Each electroactive layer can comprise a polymeric binder and optionally a plurality of conductive particles.

The high energy capacity electroactive positive electrode material can have a specific capacity of greater than or equal to about 90 mAh/g, optionally greater than or equal to about 120 mAh/g, optionally greater than or equal to about 140 mAh/g, optionally greater than or equal to about 160mAh/g, optionally greater than or equal to about 180mAh/g, optionally greater than or equal to about 200mAh/g, optionally greater than or equal to about 220mAh/g, and in certain variations, optionally greater than or equal to about 250 mAh/g.

The high power capacity electroactive positive electrode material can have a potential greater than or equal to about 1V with respect to Li/Li + during lithium ion insertion and/or absorption, optionally a potential greater than or equal to about 1.5V with respect to Li/Li + during lithium ion insertion and/or absorption.

Two exemplary, non-limiting general classes of known high energy density electroactive materials that can be used to form the positive electrode are lithium transition metal oxides having a layered structure and lithium transition metal oxides having a spinel phase. For example, in certain instances, the positive electrode can include a spinel-type transition metal oxide, such as lithium manganese oxide (Li)_(1+x)Mn_(2-x)O₄) Where x is typically less than 0.15, including LiMn₂O₄(LMO) and lithium manganese nickel oxide LiMn_1.5Ni_0.5O₄(LMNO). In other cases, the positive electrode can include a layered material such as lithium cobalt oxide (LiCoO)₂) Lithium nickel oxide (LiNiO)₂) Lithium nickel manganese cobalt oxide (Li (Ni)_xMn_yCo_z)O₂) Wherein x is more than or equal to 0 and less than or equal to 1, y is more than or equal to 0 and less than or equal to 1, z is more than or equal to 0 and less than or equal to 1, and x + y + z = 1, comprises LiMn_0.33Ni_0.33Co_0.33O₂Lithium nickel cobalt metal oxide (LiNi)_(1-x-y)Co_xM_yO₂) Wherein 0<x<1. 0 < y < 1 and M can be Al, Mn, etc. Other known lithium transition metal compounds, such as lithium iron phosphate (LiFePO), may also be used₄) Or lithium iron fluorophosphate (Li)₂FePO₄F)。

In certain aspects, the hybrid lithium-ion electrochemical cell includes a first positive electrode having a first electroactive material and/or a second positive electrode having a second electroactive material independently selected from: LiNiMnCoO₂，Li(Ni_xMn_yCo_z)O₂) Wherein x is more than or equal to 0 and less than or equal to 1, and y is more than or equal to 0 and less than or equal to 11. 0-z 1 and x + y + z = 1, LiNiCoAlO₂，LiNi_1-x-yCo_xAl_yO₂(wherein x is 0. ltoreq. x.ltoreq.1 and y is 0. ltoreq. y.ltoreq.1), LiNi_xMn_1-xO₂(wherein x is not less than 0 and not more than 1), LiMn₂O₄，Li_1+xMO₂(where M is one of Mn, Ni, Co and Al and x is 0-1), LiMn₂O₄(LMO)，LiNi_xMn_1.5O₄，LiV₂(PO₄)₃，LiFeSiO₄，LiMPO₄(where M is at least one of Fe, Ni, Co, and Mn), certain carbonaceous materials such as activated carbon, and combinations thereof.

These active materials may be mixed with optional conductive materials (e.g., particles) and at least one polymeric binder, for example, by slurry casting the active materials and optional conductive material particles with such binders as polyvinylidene fluoride (PVdF), poly (vinylidene chloride) (PVC), poly ((dichloro-1, 4-phenylene) ethylene), carboxymethylcellulose (CMC), nitrile rubber (NBR), fluorinated urethanes, fluorinated epoxides, fluorinated acrylics, copolymers of halogenated hydrocarbon polymers, epoxides, ethylene propylene diamine terpolymer rubber (EPDM), Hexafluoropropylene (HFP), ethylene acrylic acid copolymer (EAA), ethylene vinyl acetate copolymer (EVA), EAA/EVA copolymer, PVdF/HFP copolymer, polyvinylidene fluoride (PVdF), and at least one polymeric binder, Lithium polyacrylate (LiPAA), sodium polyacrylate (NaPAA), sodium alginate, lithium alginate, and combinations thereof.

In certain variations, the high power capacity electroactive material may be in one of the positive electrodes and may comprise an active material, such as carbonaceous compounds, e.g., disordered carbon and graphitic carbon/graphite, porous carbon materials including Activated Carbon (AC), carbon xerogels, Carbon Nanotubes (CNT), mesoporous carbon, template carbon, carbide-derived carbon (CDC), graphene, porous carbon spheres, and heteroatom-doped carbon materials. Can also include Faraday capacitor materials, e.g., noble metal oxides, e.g., RuO₂Transition metal oxides or hydroxides, e.g. MnO₂、NiO、Co₃O₄、Co(OH)₂、Ni(OH)₂And the like. The capacitance delivered by the faraday capacitor material is referred to as pseudocapacitance, which is essentially a rapid and reversible redox reaction. Other capacitor active materials may include conductive polymers such as Polyaniline (PANI), polythiophene (PTh), polyacetylene, polypyrrole (PPy), and the like. In still other aspects, the high power capacity electroactive material may be silicon, a silicon-containing alloy, a tin-containing alloy, a lithium titanate compound selected from the group consisting of: li_4+xTi₅O₁₂Wherein x is more than or equal to 0 and less than or equal to 3, and lithium titanate (Li)₄Ti₅O₁₂) (LTO), Li_4-x ^a _/3Ti_5-2x ^a _/3Cr_x ^a O₁₂Wherein 0 is less than or equal to x^a ≤ 1, Li₄Ti_5-x ^bSc_x ^bO₁₂Wherein 0 is less than or equal to x^b ≤ 1, Li_4-x ^cZn_x ^cTi₅O₁₂Wherein 0 is less than or equal to x^c ≤ 1, Li₄TiNb₂O₇And combinations thereof.

In certain variations, the high power capacity electroactive material may comprise an electroactive material selected from the group consisting of: activated carbon, hard carbon, soft carbon, porous carbon material, graphite, graphene, carbon nanotubes, carbon xerogel, mesoporous carbon, template carbon, carbide-derived carbon (CDC), graphene, porous carbon spheres, heteroatom-doped carbon material, metal oxides of noble metals such as RuO₂Transition metal, transition metal hydroxide, MnO₂、NiO、Co₃O₄、Co(OH)₂、Ni(OH)₂Polyaniline (PANI), polythiophene (PTh), polyacetylene, polypyrrole (PPy), and the like.

The conductive material may include graphite, other carbon-based materials, conductive metals, or conductive polymer particles. As a non-limiting example, the carbon-based material may include KETCHEN^TMBlack, DENKA^TMParticles of black, acetylene black, carbon black, and the like. The conductive metal particles may include nickel, gold, silver, copper, aluminum, and the like. Examples of the conductive polymer include polyaniline, polythiophene, polyacetylene, polypyrrole, and the like. Carbon may also be usedNanotubes and carbon nanofibers. In certain aspects, mixtures of conductive materials may be used.

The positive current collector may be formed of aluminum or any other suitable conductive material known to those skilled in the art. As described above, the positive electrode current collector may be coated on one or more sides.

In various aspects, the negative electrode includes an electroactive material as a lithium host material capable of serving as a negative terminal for a lithium ion battery. The negative electrode may thus comprise the electroactive lithium host material and optionally other electrically conductive materials, and one or more polymeric binder materials to structurally hold the lithium host material together.

For example, in one embodiment, the negative electrode may comprise an electroactive material comprising a carbon-containing compound, such as graphite, silicon oxide Activated Carbon (AC), Hard Carbon (HC), Soft Carbon (SC), graphite, graphene, carbon nanotubes, and the like. Graphite is a high energy capacity negative electrode electroactive material. Commercial forms of graphite and other graphene materials are available as electroactive materials. Other materials include, for example, silicon (Si), tin (Sn) and lithium (Li), including lithium-silicon and silicon-containing binary and ternary alloys and/or tin-containing alloys, such as Si-Sn, SiSnFe, SiSnAl, SiFeCo, SnO₂And the like. Titanium dioxide (TiO)₂) Are also suitable anode active materials. In certain variations, the negative electrode electroactive material may be a lithium titanate compound selected from the group consisting of Li₄₊ _xTi₅O₁₂Wherein x is 0-3, Li_4-xa/3Ti_5-2xa/3Cr_xaO₁₂Wherein 0. ltoreq. xa. ltoreq.1, Li₄Ti_5-xbSc_xbO₁₂Where 0. ltoreq. xb. ltoreq.1, Li_4-xcZn_xcTi₅O₁₂Where 0. ltoreq. xc. ltoreq.1, Li₄TiNb₂O₇And combinations thereof. In certain variations, the high power capacity electroactive material comprises Li_4+xTi₅O₁₂Wherein x is more than or equal to 0 and less than or equal to 3, and lithium titanate (Li)₄Ti₅O₁₂) (LTO). Lithium may be provided as an elemental metal or in an alloyed form. Other suitable negative electrode electroactive materials include ferrous sulfide (FeS), vanadium pentoxide (V)₂O₅) Titanium dioxide (TiO)₂) Iron (III) oxide (Fe)₂O₃) Iron (II) oxide (Fe)₃O₄) Iron (III) oxyhydroxide (. beta. -FeOOH), manganese oxide (MnO)₂) Niobium pentoxide (Nb)₂O₅) Ruthenium dioxide (RuO)₂) And combinations thereof.

In certain aspects, the hybrid lithium ion active battery may include a negative electrode having a negative electroactive material selected from the group consisting of: lithium metal, lithium alloy, silicon (Si), silicon alloy, silicon oxide activated carbon, hard carbon, soft carbon, graphite, graphene, carbon nanotube, lithium titanium oxide (Li)₄Ti₅O₁₂) Tin (Sn), vanadium oxide (V)₂O₅) Titanium dioxide (TiO)₂) Titanium niobium oxide (Ti)_xNb_yO_zWherein 0. ltoreq. x.ltoreq.2, 0. ltoreq. y.ltoreq.24 and 0. ltoreq. z.ltoreq.64), ferrous sulfide (FeS) and combinations thereof.

The negative electrode electroactive material may be mixed with a binder material selected from the group consisting of: as non-limiting examples, polyvinylidene fluoride (PVdF), poly (tetrafluoroethylene) (PTFE), Ethylene Propylene Diene Monomer (EPDM) rubber, or carboxymethylcellulose (CMC), Nitrile Butadiene Rubber (NBR), styrene ethylene butylene styrene copolymer (SEBS), styrene butadiene styrene copolymer (SBS), lithium polyacrylate (LiPAA), sodium polyacrylate (NaPAA), sodium alginate, lithium alginate, and combinations thereof.

Suitable additional conductive particles may comprise a material selected from the group consisting of: carbon-based materials, conductive metals, conductive polymers, and combinations thereof. The carbon-based material may include, as non-limiting examples, carbon black, KETCHEN^TMBlack granules, DENKA^TMBlack particles, acetylene black particles, graphite, graphene oxide, acetylene black, carbon nanofibers, carbon nanotubes, and the like. The conductive metal particles may include nickel, gold, silver, copper, aluminum, and the like. Examples of the conductive polymer include polyaniline, polythiophene, polyacetylene, polypyrrole, and the like. In some aspects of the present invention, the first and second electrodes are,mixtures of conductive particulate materials may be used.

The negative electrode current collector may be a copper collector foil, which may be in the form of an open mesh or a thin film. The current collector may be connected to an external current collector tab (tab).

As described above, the battery may have a laminated cell structure comprising an anode or negative electrode layer, a cathode or positive electrode layer, and an electrolyte/separator interposed between the negative and positive electrode layers. The negative and positive current collectors may be coated on both sides with a cathode and an anode layer, respectively (double-sided coating).

The electrode may be prepared by mixing the electrode active material in a slurry with a polymer binder compound, a non-aqueous solvent, optionally a plasticizer, and, optionally if desired, conductive particles. The slurry may be mixed or stirred and then thinly applied to a substrate by a doctor blade. The substrate may be a removable substrate, or alternatively may be a functional substrate, such as a current collector (e.g., a metal grid or mesh layer) attached to one side of the electrode film. In one variation, heat or radiation may be applied to evaporate the solvent from the electrode film, leaving a solid residue. The electrode film may be further consolidated, wherein heat and pressure are applied to the film to sinter and calender it. In other variations, the film may be air dried at moderate temperatures to form a self-supporting film. If the substrate is removable, it is then removed from the electrode film, which is then further laminated to the current collector. For either type of substrate, extraction or removal of the remaining plasticizer may be required prior to incorporation into the battery cell.

When forming a composite electrode comprising a polymer binder matrix, greater than or equal to about 50 wt.% to less than or equal to about 97 wt.% of the negative electrode electroactive material, optionally greater than or equal to about 0 wt.% to less than or equal to about 30 wt.% of one or more conductive additives; and optionally greater than or equal to about 0 wt.% to less than or equal to about 20 wt.% of one or more binders.

Alternatively, the active material, e.g., lithium metal, may be deposited, e.g., by a coating formation process, such as Atomic Layer Deposition (ALD) or physical vapor deposition or chemical vapor infiltration, or combined with the current collector as a pre-formed film.

Thus, individual cells can be assembled in a laminated cell structure comprising an anode layer, a cathode layer, and an electrolyte/separator between the anode and cathode layers. In general, an electrochemical cell may refer to a unit that may be connected to other units. A plurality of electrically connected cells, such as those stacked together, may be considered a module. A package generally refers to a plurality of operatively connected modules that may be electrically connected in various combinations of series or parallel connections. The battery module may thus be enclosed in a pouch structure, a housing, or arranged with a plurality of other battery modules to form a battery pack. In certain aspects, the battery module may be part of a prismatic hybrid battery.

In one example, a negative electrode layer having an electrode active material and optionally conductive particles dispersed in a polymeric binder matrix may be disposed on the negative current collector. A separator can then be placed on the negative electrode element, the separator covered with a positive electrode film comprising an electroactive material, optionally conductive particles, dispersed in a polymer binder matrix. The positive current collector, such as an aluminum collector foil or grid, completes the assembly. As described above, the negative and positive current collectors may be further coated on one or more sides. The tabs of the current collector element may form each terminal of the battery. In this manner, multiple cells may be formed to produce a wound cell core containing a stack of cells, a jellyroll, or different cells. The protective bagging material covers the battery and prevents air and moisture infiltration. Into this pouch, a liquid electrolyte suitable for lithium ion transport may be injected into the separator (and may be absorbed into the positive and/or negative electrodes). In certain aspects, the laminated battery is further hermetically sealed prior to use.

The foregoing description of the embodiments has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not explicitly shown or described. It can also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.

Claims

1. A hybrid lithium-ion electrochemical cell comprising:

a first electrode having a first polarity and comprising a first electroactive material that reversibly cycles lithium ions;

a second electrode having the first polarity and comprising a second electroactive material that reversibly cycles lithium ions different from the first electroactive material;

at least one third electrode comprising a third electroactive material that reversibly cycles lithium ions and having a second polarity opposite the first polarity; and

at least one voltage change component in electrical communication with the first electrode and the second electrode, wherein the hybrid lithium-ion electrochemical cell has a first operating state corresponding to charging and a second operating state corresponding to discharging, wherein the at least one voltage change component is configured to induce a voltage drop in the first operating state.

2. The hybrid lithium-ion electrochemical cell of claim 1 wherein the at least one voltage altering component is selected from the group consisting of: diodes, p-n junction diodes, schottky diodes, triodes, transistors, thyristors, field effect transistors, electronic devices comprising p-n junctions, and combinations thereof.

3. The hybrid lithium-ion electrochemical cell of claim 1, further comprising at least two voltage altering components in electrical communication with the first electrode and the second electrode, wherein the first voltage altering component is configured to induce a first voltage drop in either the first or second operating state and the second voltage altering component is configured to allow current to pass in the other of the first or second operating state.

4. The hybrid lithium-ion electrochemical cell of claim 1, wherein the first and second electrodes are connected in parallel or in series.

5. The hybrid lithium-ion electrochemical cell of claim 1 wherein the at least one voltage change component further comprises a plurality of voltage change components, wherein the plurality of voltage change components are connected in series, wherein the voltage drop is a cumulative voltage drop produced by the plurality of voltage change components or the plurality of voltage change components are connected in parallel to reduce resistance.

6. The hybrid lithium-ion electrochemical cell of claim 1 wherein the voltage drop is greater than 0V and less than or equal to about 5V.

7. The hybrid lithium-ion electrochemical cell of claim 1 wherein the first electrode is a first positive electrode and the second electrode is a second positive electrode, wherein the first electroactive material is selected from the group consisting of: LiNiMnCoO₂，Li(Ni_xMn_yCo_z)O₂) Wherein x is 0-1, y is 0-1, z is 0-1 and x + y + z = 1, LiNiCoAlO₂，LiNi_1-x-yCo_xAl_yO₂(wherein x is 0. ltoreq. x.ltoreq.1 and y is 0. ltoreq. y.ltoreq.1), LiNi_xMn_1-xO₂(wherein x is not less than 0 and not more than 1), LiMn₂O₄，Li_1+xMO₂(where M is one of Mn, Ni, Co and Al and 0. ltoreq. x.ltoreq.1), LiMn₂O₄(LMO)，LiNi_xMn_1.5O₄，LiV₂(PO₄)₃，LiFeSiO₄，LiMPO₄(wherein M is at least one of Fe, Ni, Co and Mn), activated carbon and combinations thereof, the second electroactive material being selected from: silicon oxide activated carbon, hard carbon, soft carbon, porous carbon material, graphite, graphene, carbon nanotube, carbon xerogel, mesoporous carbon, template carbon, carbide-derived carbon ((C))CDC), graphene, porous carbon spheres, heteroatom-doped carbon materials, metal oxides of noble metals, RuO₂Transition metal, transition metal hydroxide, MnO₂、NiO、Co₃O₄、Co(OH)₂Ni (oh), Polyaniline (PANI), polypyrrole (PPy), polythiophene (PTh), and combinations thereof; and the at least one third electrode is a negative electrode, and the third electroactive material is selected from: lithium metal, lithium alloy, silicon (Si), silicon alloy, silicon oxide activated carbon, hard carbon, soft carbon, graphite, graphene, carbon nanotube, lithium titanium oxide (Li)₄Ti₅O₁₂) Tin (Sn), vanadium oxide (V)₂O₅) Titanium dioxide (TiO)₂) Titanium niobium oxide (Ti)_xNb_yO_zWherein x is 0. ltoreq. x.ltoreq.2, y is 0. ltoreq. y.ltoreq.24 and z is 0. ltoreq. z.ltoreq.64), ferrous sulfide (FeS) and combinations thereof.

8. The hybrid lithium-ion electrochemical cell of claim 1, wherein the first electroactive material has a first electrochemical potential and the second electroactive material has a second electrochemical potential, wherein a difference between the second electrochemical potential and the first electrochemical potential defines a first predetermined voltage difference, wherein the voltage drop corresponds to the predetermined voltage difference.

9. The hybrid lithium-ion electrochemical cell of claim 1 wherein the first electrode is a first negative electrode and the second electrode is a second negative electrode, wherein the first electroactive material is selected from the group consisting of: lithium metal, lithium alloy, silicon (Si), silicon alloy, silicon oxide activated carbon, hard carbon, soft carbon, graphite, graphene, carbon nanotube, lithium titanium oxide (Li)₄Ti₅O₁₂) Tin (Sn), vanadium oxide (V)₂O₅) Titanium dioxide (TiO)₂) Titanium niobium oxide (Ti)_xNb_yO_zWherein x is 0 ≦ 2, y is 0 ≦ 24 and z is 0 ≦ 64), ferrous sulfide (FeS), and combinations thereof, and the second electroactive material is selected from the group consisting of: silicon oxide activated carbon, hard carbon, soft carbon, porous carbon material, graphiteAlkenes, carbon nanotubes, carbon xerogels, mesoporous carbon, template carbon, carbide-derived carbon (CDC), graphene, porous carbon spheres, heteroatom-doped carbon materials, metal oxides of noble metals, RuO₂Transition metal, transition metal hydroxide, MnO₂、NiO、Co₃O₄、Co(OH)₂、Ni(OH)₂Polyaniline (PANI), polypyrrole (PPy), polythiophene (PTh), and combinations thereof; and the third electrode is a positive electrode and the third electroactive material is selected from: LiNiMnCoO₂，Li(Ni_xMn_yCo_z)O₂) Wherein x is 0-1, y is 0-1, z is 0-1 and x + y + z = 1, LiNiCoAlO₂，LiNi_1-x- _yCo_xAl_yO₂(wherein x is 0. ltoreq. x.ltoreq.1 and y is 0. ltoreq. y.ltoreq.1), LiNi_xMn_1-xO₂(wherein x is not less than 0 and not more than 1), LiMn₂O₄，Li_1+xMO₂(where M is one of Mn, Ni, Co and Al and 0. ltoreq. x.ltoreq.1), LiMn₂O₄(LMO)，LiNi_xMn_1.5O₄，LiV₂(PO₄)₃，LiFeSiO₄，LiMPO₄(wherein M is at least one of Fe, Ni, Co, and Mn), activated carbon, and combinations thereof.

10. An electrochemical device, comprising:

a first battery cell, comprising:

at least one first electrode having a first polarity and comprising a first electroactive material that reversibly cycles lithium ions;

a first electrical terminal connected to the at least one first electrode;

at least one second electrode comprising a second electroactive material that reversibly cycles lithium ions having a second polarity opposite the first polarity; and

a second electrical terminal connected to the at least one second electrode;

a second battery cell, comprising:

at least one third electrode having the first polarity and comprising a third electroactive material that reversibly cycles lithium ions;

a third electrical terminal connected to the at least one third electrode;

at least one fourth electrode having the second polarity and comprising a fourth electroactive material; and

a fourth electrical terminal connected to the at least one fourth electrode, wherein the first and third electrical terminals are electrically connected and the second and fourth electrical terminals are electrically connected; and

at least two voltage change components in electrical communication with the first electrical terminal and the third electrical terminal, wherein the electrochemical device has a first operating state corresponding to charging and a second operating state corresponding to discharging, wherein a first of the at least two voltage change components is configured to induce a voltage drop in the first operating state and a second of the voltage change components is configured to allow current flow in the second operating state.